Comparative Results of Co-Operating Laboratories on the Shearing Resistance of Ottawa Sand Citation Minasian, John Kachig (1944) Comparative Results of Co-Operating Laboratories on the Shearing Resistance of Ottawa Sand. Master's thesis, California Institute of Technology. doi:10.7907/yg5j-1643. https://resolver.caltech.edu/CaltechTHESIS:03282025-184928531 Abstract No abstract. Item Type: Thesis (Master's thesis) Subject Keywords: (Civil Engineering) Degree Grantor: California Institute of Technology Division: Engineering and Applied Science Major Option: Civil Engineering Thesis Availability: Public (worldwide access) Research Advisor(s): Converse, Frederick James Thesis Committee: Unknown, Unknown Defense Date: 1 October 1944 Record Number: CaltechTHESIS:03282025-184928531 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:03282025-184928531 DOI: 10.7907/yg5j-1643 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 17101 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 31 Mar 2025 19:36 Last Modified: 31 Mar 2025 19:40 Thesis Files PDF - Final Version See Usage Policy. 35MB Repository Staff Only: item control page

COMPARATIVE RESULTS 0F CO-OPERATING LABORATORIES ON THE SHEARING RESISTANCE OF O'l'TAWA S.AND .THESIS BY: JOHN KACHIG MINASIAN Submitted as partial fulfillment of the requirements f'or the Degree of Master of Science in Civil Engineering CALIFOR.i.~IA INSTITUTE OF TECHNOLOGY PASADENA, CALIFORNIA October, 1944 PHEli'ACE The Subcommittee on Shearing Resistance of Sails was organized in 1937 as part of the A.S.T.M. Committee D 18 on Soils for Engineering Purposes. ·The aim of this subcornmi ttee was to study the variations in results of different shear testing machines in order to establish standards of equipment and procedure in the determination of the shearing resistance of soils. To study the factors affecting the measurement of shearing resistance in soilst the subcommittee selected two materials for investigation. The first was Ottawa Sand representing the ultimate of a cohesionless material, a standard for comparing the various,. shear testing equipments. The second was a Detroit clay furnished by Prof. w. S. Housel, University of Michigan, representing a soil'- primarily cohesive. ------ Only the comparative test results on Ottawa Sand are included in this thesis. ACKNOWLEDGEMENT The author wishes to express his appreciation for the guidance and assistance given by Professor Frederick J. Converse in the preparation of this thesis and for access to the results of the various co-operating laboratories. CO-OPERATING LABORATORIES 1. California Institute of Technology Vey and Silberstein 2. Columbia University Prof. D.M.Burmister 3. University of Michigan A. L. Davies 4. Princeton University Prof.G.P.Tschebotareff 5. U.S.Engineer Laboratory Fort Peck, Montana 6. U.S.Engineer Office Ithaca, New York 7. U.S.Dept. of Interior Washington, D.C. c'o.NTENTS Shear Research Program - Ottawa Sand 1 Discussion on Testing Apparatus 2 Conclusions: 3-5 Cooperating Laboratories 6-8 Graph - Shearing Tests on Ottawa Sand. Dense State. Ultimate Shearing Stress vs. Normal Load. 9 Graph - Shearing Tests on Ottawa Sand. Loose State. Ultimate Shearing Stress vs. Normal Load. 10 Summary of Test Results. Co-operating Laboratories: California Intitute of Technology 11-15 Columbia University 16-22 University of Michigan 23-30 Princeton Universi~y 31-34 U. ~:;. !!:ngineer Laboratory F'ort Peck, :Montana 35-39 U.S.Engineer Office Ithaca, :New York 40-46 U.S.Dept. of Interior Washington, D.C. 47-51 I SHEAR RESEARCH PROGRAM - OT-TAWA SAND • Sand passing the No. 20 sieve and retained on the No. 10 sieve is to be compacted in the shear machine at three d·e nsities, (a) The loosest possible condition (b) The densest state obtainable by vibration,or otherwise (c) A relative density of 50% For each density the shearing strength . of sand should be obtained under the following normal pressures in tons per sq. ft. perpendicular to the shearing plane:2.0, 3.0 tons per sq. ft. 0.1, 0.3, 0.5, 0.7, 1.0, If time is not available to run the full series, it is suggested that alternate _pressures in the above list be omitted. It is proposed that the shearing load be applied in increments of about one-eighth of the estimated ultimate strength, waiting until motion had ceased before applying each increment. If a different method of testing than the preceding is standard for any particular laboratory, it is suggested that this method be also used, and a detailed description turned in with the test results. Plot normal stress in tons per square foot as abscissas, and ultimate shearing resistance in pounds per square inch as ordinates. Plot the curve for each density separately, but plot all curves on the same sheet. DISCUSSION ON TESTING APPARATUS The shearing apparatus of all the cooperating lab9ratories are of the direct-shear type. Only the University of Michigan has the double shear type; all the others are single shear . . Three laboratories place their s~ples in a circular shear box, whereas the other four laboratories use a square shear box. Most of the shear boxes differ in thickness~ Various methods were used in applying both normal and shearing loads. Rate of shear loading varied from a constant ,applied force to a loading applied in increments. Detailed description of all the shear testing apparatus of the various co-operating laboratories are included in the body of the thesis under the condensed reports on the testing of Ottawa Sand by each laboratory. CONCLUSIONS 1. Angle of Internal Friction,¢. There is no correlation between the angles of internal friction, ¢, and the various voids of Ottawa sand. For the same dense void of 33.3%, the angle of internal , friction,¢, varies from 34° 45' to 54° 20'. Likewise, for the loose dry state, the voids range from 37.3% to 41%, whereas the angles of internal friction vary from 23° 00' to 43° 40'. The largest¢ value based upon ultimate shearing stress was given by the double shear testing apparatus of. the University of Michigan. The graphs on pages 9 and 10 show the complete range of¢ values for both dense and loose states. Although the results .of these series of tests are not entirely consistent, it appears that the thickness of the sample has an influence on the value of the angle of friction. The thicker samples tend to give the smaller values for¢. There is also a tendency for the shear boxes of larger areas to give the.smaller values for¢. However, other factors of the shearing apparatus influence the relative¢ values. These are friction in the apparatus, non-uniform distribution of normal load, pronounced boundary effects in smaller • frames and progressive failure in dense sands. 4 These series of tests show that rate and manner of loading do not appear to have any appreciable influence on the value of the angle of internal friction. However, the results of the U.S. Engineer Laboratory at Fort Peck, Montana, show that the larger load increments in the A.S.T.M. method produce a lower ultimate shearing strength for the sample than was found in the corresponding test made according to the Fort Peck method. The laboratories co-operating in the shearing testing program under the A.S.T.M. program are few in number and conclusive results cannot be drawn. Each shear testing machine should be calibrated by comparing vri th actual field observation of the angle of internal friction for various materials. 2. Comparison of Voids at Dense, Medium and Loose States. The table on the proceeding page shows no correla- tion between the voids at dense, medium and loose states \ for the various laboratories. For the purpose of comparison, the dense state of the Ottawa sand is taken as 100% and the medium and loose states are calculated as percentages of the dense state. s OTTAWA SAND Table - Comparison of Voids at Dense, Medium & Loose States C.oopera ting L~boratory State of Sand Dense Medium State of Sand Loose Dense Medium I Loose % of Dense State Voids (1) Cal-Tech 32% 38% 100% 84.3% ( 2) Columbia Univ. 33.3% 39.8% 100% 83.9% ------ ( 3) Univ.of Michigan 33-4% 35.0% 38.0% 100% 41. Oo/; lOO~b 88.0% 95-5% -- { 4) Princeton Univ. 31.0% ·------ ( 5) U.S.Eng.Lab., Fort Peck,Mon. 36.~0 ______ __, ___ 38 -4~~ 75-5% ------- ------· 40. 87s 100% 93. 8o/~ 88.3% - (6) u.s.Eng.of Ithaca Not given New York {7) U.S.Dept. Int. Washington, D.C. 33-..4% 35. O~o 37-3% 100% 95.5% 89. 5J; ! : SHMMARY OF TEST RESULTS CO-OPERATING LABORATORIES Tests on Ottawa Sand 1. Ultimate Shearing Stress for Dense State. Co-operating Laboratory Voids 1. Cal-Tech Dense, DriJ 32.0% 0.085 11 /min. 6.12 dia. J.94 Single 24°30' 0.04 2. Columbia Dense,Dry 33.3% 0.05 11 /min 6.35x8.90 2.60 Single 34°45' Dense,Dry Dense,Dry 33.4% 33,,4'/, Eq.Inc.at 10 1 3#/ min. 3. 50 dia. J.50 dia. 2.50 2. 50 Double 51°15' Double 54° 55' 0.40 Dense,Dry 33o4% Constant 11.48 dia. 7.62 Double 54°20 6.0x6.0 6.0x6.o 1.62 1.62 Single 39°00 1 0.11 Single 34°40 1 0.12 Univ. 3. Univ. of Michigan Rate of Loading Shear Bo.x Sin.or Dimensions Thick. Double ems. ems. Shear State of sand ¢ ', 0.1 O.J Ulti.rnate Shearin.a stress• 'T'ons /sn. Ft. N ::: Normal Load: Tons /Sq. Ft. 2.0 3.0 0.5 0.7 1.0 0.17 N=0.29 N=0.55 0.21 0.41 1 0.65 0.65 N=0.36 0.55 .o.86 0.90 0.3 0.44 0.43 Oo53 0,,46 Oo45 4. Princeton Dense,Dry Univ. Dense,Moi 31.0% Eq.Inc .&Const. Constant 35.0% 5.u .s .Eng .Lab Dense,Dry Fort Peck,Mon Dense,Dry 36.0% 36.CJ/o Increments Increments 10.15xl0.15 2.54 10.15x10.15 2.54 Single 29°10 1 0.03 Single .35°00 1 0.04 0.10 0.13 0.31 0.32 6.U.S.Eng.Off Dense,Dry Ithaca, N. Y. [)ense,Moi Not given do Constant 10.15xl0.15 Single 24°00 1 0.16 0.25 Constant 10.15xl0.15 Single 2/~0 40 I 0.24 0.24 7.u.s.Dep.Int Dense,Dry Wash.,D.C. 33.N!o Increments 6.35 dia. 2. 2.54 0.25 0.17 0.72 1.30 N-=l.06 N=l.57 0.72 1.09 N=2.09 1.49 2.91 1.65 3.02 1.13 1.55 N-=0.72 N=L44 N=2.16 0.98 2.05 2.99 1.22 Remarks J.5 4.0 4.08 4.45 N J ,, 60 5.c:£ 2 0.79 0.73 1.60 0.59 o.68 1.04 1.26 1.72 2.07 N=l.00 N=l.32 0.49 0.59 N=l.00 o.,~5 0.89 1.35 0.88 1.38 2.41 ; 2.12 A.S.T.M. Method Fort Peck Method 1.58 N=0.234 N=0.476 N=O. 718 N=0.960 N=l.203 0.88 Oo60 0.32 1.17 1.46 Single 50°00 1 Maximum Shearing Stress for Dense state Rate of Loading Shear Box Sin.or Dimensions Thick. Double ems. Shear ems. 32.0$ 0.085 11 /min. 6.12 dia. J.94 Single 35•50 I 0.05 33.3% 0.05 6.35x8.90 2.60 Single 43°10 1 N=0.29 0.36 Not given do Const,3,nt 10.15xl0.15 Single 29°20 1 0.22 Constant 10.15xl0.15 Single 32•20 1 0.22 6.35 dia. Single 50°00 1 State of Sand Voids 1. Cal-Tech Dense,Dry 2. Columbia Univ. Dense,Dry Co-operating Laboratory 6.tJ .s . ~;ne .Off Dense,Dry Ithaca,N.Y. Dense,Moi 7.U.S.Dep.Int Dense,Dry Wash., D.C. 33.4% 11 /min. Increments 2.54 ,¢ 0.1 0.3 Uaxir:mm Shearine- Stress• Tons /.c:. c•. Ft. N = Normal Load: Tons/Sy_ .Ft. 2.0 1.0 J .O 0.7 0.5 0.25 0.46 N=O. 55 o.64 0.38 • 1.,32 2.09 N==l.06 N=l. 57 1.16 1.57 N=2.09 2.10 N=l.00 N=l.32 o.86 o.67 0.35 N=l.00 0.66 0.34 N:0.234 N=0.476 NU718 0.60 0.88 0.32 Remarks )o5 1.20 1.70 2.05 1.19 1.88 2.16 N=0.960 N=l.203 1.17 1.46 4.0 2.61 7 SUMMARY OF TEST RESULTS CO-OPERATING LABORATORIES Tests on Ottawa Sand 3. Ultimate Shearing Stessfor Medium State. Co-operating Laboratory state of ·Sand Voids Med., Dry Med., Dry 35.0% 35.0% Eq.Inc.at 10 1 Med.,Dry ' 5.U.S. Eng .Lab Med., Dry Fort Peck,Mon Med.,Dry 3. Univ. of Michigan Rate of Loading Shear Box Sin.or Dimensions Thick Double ems. ems. Shear 0.1 3#/min. J.50 dia. J.50 dia. 2.50 2.50 Double 47'20 1 Double 49°45 1 0.22 35.0% Constant 11.48 dia. 7.62 Double 45°10 1 38.4% 38.4% Increments -, 10ol5xl0.15 Increments 10.15xl0.15 2.54 2.54 Single 26°50 1 0.02 Single 32°05 1 0.02 35.0% Increments .. ,. 7.U.S.Dep.Int Med., Dry Wash., D.C. r/J 6.35 dia. 2.54 Single 44°20 1 0.3 0.:57 N=Oo36 0.50 0.13 0.12 Ultimate Shearin~ -stress: Tons/sq.Ft. N Normal Load: Tons/Sq.Ft. 0.5 1.50 2.0 0.7 LO = 0.89 0.88 0.23 0.30 1.15 LlO N::0.72 0.91 1.39 1 • .36 0.39 0.39 . 0.55 0.62 2.52 2.61 N,..1.44 N=2.16 1.55 2 • .37 N-=0.234 N--0.476 N=0 .. 7H N=0.960 N::1.203 0.24 0.47 . 0.72 1.17 0.97 0.90 1.17 Remarks 3.0 3,58 3 73 1.54 1.85 3.5 4.0 N=J.60 J.64 A.S.T.M.Method Fort Peck Method SUMMARY OF TEST RESULTS CO-OPERATING LABORATORIES Tests on Ottawa sand .\. Ultimate Shearing Stress for Loose State. Co-operating Laboratory state of Sand Rate of Loading Shear Box Dimensions Thick. ems. ems. Sin.or Double Shear Voids 1. Cal-Tech Loose,Dry 38.0% 0.085 11 /min. 6.12 dia. 3o94 Single 23°00 1 0.05 2. Columbia Loose,Dry 39.8% 0.05 11 /min. 6.35x8.90 2.60 Single 32°00 1 Loose,Dry Loose,Dry 38.0f, Eq.Inc.at 10 1 38.0% 3#/min. 3~50 dia. 3o50 dia. 2.50 2.50 Double 42°40' Double 43°40 1 O.?.l Loose,Dry 38.0% 1L48 dia. 7.62 Double 27°00 1 . 6.0x6.o 6.0x6.0 1.62 1.62 Single 32•00 1 0.09 Single 30°30 1 0.08 0.24 Univ. 3. Univ. of Michigan Constant ti 0.1 0.3 Ultimate ShearinH Stress! Tons /sa. Ft. N =Normal toad: Tons/Sq.Ft. 2.0 Oo 5 LO 1.50 3.0 0.7 0.35 o.68 N=l.06 o.69 N=l. 57 N:a2.09 1.03 1.34 0.86 0.76 N::0.72 0.64 0.91 1.19 1.68 2.14 N=l.44 N-=2.16 0.92 1.39 3.05 3.08 0.38 0. 33 0.48 G.71 0o59 1.29 1.90 1.78 0.32 0.34 0.37 0.57 0.89 1.12 1.31 1.65 0.46 0.47 • 0.90 0.11 N.. 0.29 Nca0.55 0.22 0.38 0.37 N-"0.36 0.45 0.70 0.57 4. Princeton Loose,Dry Loose,Moi 41.0% Eq .Inc .&Const Constant 47.0/u 5.U.S.Eng.Lab Loose,Dry Fort Peck,Mon Loose,Dry 40.8% 40.8% Increments Inceements 10.15.xl0ol5 2.54 10.15.xl0.15 2.54 Single 24°00' Single 29°45 1 0.13 0.14 0o20 0.31 6.u.s.Eng.0ff Loose,Dry Ithaca,N.Y. Loose,Moi Not given Constant Constant 10.15.xl0.15 10.15.xl0.15 Single 24°00' Single 25°40' 0.14 0.13 0.23 7.U.S.Dep.Int Loose,Dry Wash.,D.C. 37.3% Increments 5o o 0.23 .. 3.5 4o0 Remarks 1.19 N=3.60 2.04 {. 1.34 1.44 A.S.T.M. Method Fort Peck Method 1.88 N=0o23L N=0.476 N-"0.718 N==0. 960 N=l.203 N=l.445 N=l.687 6.35 dia. 2.54 Single 36°00 1 o·.70 0.21 0.38 0.3 Maximum Shearing Stress: Tons/Sq.Ft. N .; Normal Load: Tons'Sq.Ft. 2.0 0.5 0o7 L60 1.50 3.0 0.52 0.90 1.01 1.25 Maximum Shearing Stess for Loose State. Rate of Loading Shear Box Sin.or Dimensions Thick. Double ems. ems. Shear 38.0% 0.085 11 /min. 6.12 dia. 3.94 Single 23Q 50' 0.07 Loose,Dry 39.8% 0.05 11 /min. 6.35x8.90 2.60 Single 32°00 1 6.u.s.Eng.0ff Loose,Dry Ithaca..1 N. Y. Loose,Moi Not given Constant Constant 10.15xl0.15 10.15x10.15 7.U.S.Dep.Int Loose,Dry 37.3% Increments Co-operating Laboratory State of Sand Voids 1. Cal-Tech Loose,Dry 2. Columbia 6.35 dia. 2.54 ~ Single 26°40, Single 25°40 1 Single 36°00 1 0.1 0.13 0.24 N=0.29 N==0.55 0.22 0.38 0.14 0.13 0.25 0o24 N=0.65 0.30 0.36 0.76 N-=1.06 o.69 N=l. 57 N=2.09 1.03 1.34 0.49 0.§1 0.99 0.94 Remarks 3.5 4.0 1.24 1.48 1.48 N""0.234 N=0.476 N::.0.718 N-.0.960 N:1.203 N=l.445 N=l.687 0.90 1.01 0.21 o.Js 0.70 0.52 1.25 1.91 1.98 q • ' ! 1 '"f . 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The Shear Testing Machine consisted of the following important parts: (1) A lever to connect the motor to the machine. (2) Two gears, one small-connected directly to the motor, and one large-connected to the machine. These gears provided a speed reduction such that no appreciable change of shear- ing speed is experienced with changes of the normal load. (3) A lead screw on the shaft of t Le lar r e gear operated in moving ( 4) the r,1e·tal frame containing the lower rinr. ( 5) A dial cage attached to ·tilis lovrnr frwne which indicated the amount of movement with resi)ect to (6) the stationary to1;, fram.e. 'rhis frarr.:.e consisted of two semicircular r,arts - one stationary and one removable. 'r he removable part provided for f ilac:i.ng and remov-in 0 t1ie sam_p le. (7) A dial ga~e was attached to the .lower moving frame so as to give the shearing force at any time. ( 8) Apparatus for appl ying various :noraal loads to tlH3 to:p face of tb e soi 1 sample. This consist ed. of' o. ::orous st one II CALIFORNIA INSTITUTE OF TECHNOLOGY Vey and Silberstein Testing Apparatus 'I'ests were performed on a Two Ring Direct Shear Testing r\~achine. Ring area = t1. 56 square inches. 2,41 inches or 6.12 centimeters. Ring diameter = Sample thickness= l i inches. The Shear Testing Machine consisted of the following im1>0rtant parts: (1) A lever to connect the motor to the machine. (2) Two gears, one small-connected directly to the motor, and one large-connected to the machine. These gears provided a speed reduction such that no appreciable change of shear- ing speed is experienced with changes of the normal load. (3) A lead screw on the shaft of t t e larse gear operated in moving ( 4) the me·tal frarae containinr the lower rinr. ( 5) A dial gage attached to ·this lower frame which indicated the amount of movement with respect to (6) the statiorrn.ry to1) frame. 'rl1is frarn.e consisted of two -- s erni circular _p arts - one stationary ar1d one removable. 'rhe removable l)art provided for plE:i.c1.ng and remov-inc tlie . sample. (7) A dial gare was attached to the .lower moving frame so as to ci ve the shenrinf force at any ti1,1e. ( 8} Apparatus for aprilying various nor;:;ial loads to the top f,:ice of the soil sample. .Chis consisted. of' o. ;orous stone IC:. C. :,.LI Yom ;rA. I ? 3'I'I'rt.J']:1E OF TEC-,]E OLOGY Vey and Silberstein ·r estirL7 A12.£E,ratus (Cont'd) i " thick p laced on the top face of t h e soil. On this r orous stone was :p laced a si milar di an1eter metal disc with a small hole on top ·tor a metal ball. Ba lanced on t h is metal was a h orizontal. bar from which varying loads were hung. The s p eed of ·c11 e shearing was u te. o .085 inc h es per min- 3efore lllacinc t h e two ring samp le in the machine, the rin: s we re carefully cleared or separated of each other so there wa s n o :t.·uboi nf a z ainst e a c.h oth er. The intersection of the two r ings coincided with the sli p pl ane of ti1e 1t,.ovab le frc..n e &nd st c tio nor/ top fr 2<.me. These tests indic a te t ha t t he relative com ,act fo n of t l1 e s and has little or no effec t u p on the s h earin g st r encth of tlrn s end f.o:i:· low nor1:1a l loads. /j Vey and Silberstein CALI F ORNIA I l\IS'I'ITUTE OF '.rEChNOLOGY Tests on Ottawa Sand 1. M.aximwn Shearing Stre ss State of Sand Voids Dense, dry 32% Rate of Loading Max.ShearinP Stress: Tons/sc.ft. Normal Load: Tons/sc.ft. 0 .1 0.5 0.7 1 2 3 ¢ 0 iJ3 5" / min. 35°50' 0.05 0.25 0.46 o. J _8 1.32 Loose, dry 38% 0.085"/min 23°50 0.07 0.13 0.24 0.36 0.76 2.09 1.24 I 2. Ultimate Shearing Stress ·- Ra te of Loading Ult.Shearilw: Stress: Tons/so.ft NorrnEtl Load: Tons/so.ft. 2 1 0.1 0.5 0.7 3 . State of Sand Voids Dense,dry 32% 0.085"/min. 24° 30' 0.04 0.17 0.25 Loose,dry 38% 0.085"/min. 23°00' ¢ -..~. 0.05 0.11 0.23 0.17 0.72 1.30 0.35 o.68 1.19 /4- /6 COLU11IBI.A. UNIVERSITY t rof. D. M. Burmister c.restinG Apparatus The shear box, 2} in. x 3i in., is of t h e direct- shear Harvard t ype, e qui pp ed vii th a metal tooth grid for the tests on Ottawa sand, and with coarse grade porous stones for the tests on the Detroit clay. T'h e noreial p ressure is app lied on t h e shea ring bench b y means of a simp l e counte r balanced beam s y stem a nd dea d wei ghts. The horizont a l s h e a ring load is applied by a motor-op erate d gear-reduction device throug h a loa di ng b a r, which permits either of t wo shear tests to be made independentl y of the other. The horizontal shearing load is measured by means of a calibrated loading ring, fitted with an Ames dial to indic a te t h e deflection of the ring under load. The capacit y of t h e loading ring is about 700 lb. at two revolutions of the 1/10,000 A.mes dial. The horizontal shearing 0.eformation and the v e rtical expansion or compression of the soil during she a ring were me a sured by the .iJnes dial as indicated. The shear loading device is of the "constant strain" or strain-control t ype, the rate of shea ring being controlled by means of a rheostat and a time-delay relay. The upper half of the s h ear box is fi~ed and attached to the c a librated loading ring. The lower half of the shear box is movable and attached to loading standard. Tests on Ottawa Sand In each case a known wei ght of the dried ma terial was p laced in the shear box in layers, brought to the desired condition of density, and carefully leveled off with a special ad- 17 COLlTI,IBIA UNIVERSITY Frof. D. M. Burmister Tests on Ottawa Sand (Cont'd) justable screed. The initial thickness of the layer was care- fully determined by means of a calibrated straddle gage and an .Ames dial after correcting the volume of the sand for the teeth of the grid, the voids ratio was computed. Two of the series of tests contemplated were completed, for two limiting density states - about t he loosest possible condition with an average voids ratio of about 0.66, and a very dense condition with an avera Ee voids ratio of about 0.50. The loose state was obtained by permitting the sand to flow gently out of a small funnel, spreading the sand in layers by moving the funnel back and forth in a regular pattern to fill the shear boxe 'rhe dense state was obtained by applying vibrating blmvs to t h e up1Jer grid until no further volume decrease could be detec·ted by the straddle gage. 'l1he initial voids ratio in these tests refers to the voids, either in the loose or dense condition, res1)ecti vely, under the desired normal loading . This initi a l voids ratio vms comJ1uted after observing the change in the vertical dial reading upon applic at ion of the desired normal loade In the loose state, the shearing stress increases gradua lly and continuously to a maxi mum. ·whic h. is reached at a rather lar ge ho rizontal deformation of about Q.20 in. for a samp le 0.80 in. thick. On the other hand, in t h e dense state, the shearing stress inc r e ,~1ses ra pidly to a much higher .maximum than for the loose state, which occurs at quite a small horizontal deformation, comparatively of about 0.025 ino Thereafter with increasing 18 r r of . C OL1JMBIA UNIVERSITY D. T•,~• Burmi st er Tests on Ottawa Sand (Cont'd) horizontal deformation the stress drops off in a characteristic fashion quite rapidly to a value about two-thirds to three- fourths of the maximum value. This is of the nature of a rupture failure and is characteristic of shearing fail~re in the dense state. In the loose state the failmre is more of the nature of a plastic flow. Conclusions A comparsion with the value obtained for the ultimate stress shows that the loose state and ultimate shear stress for the dense state hav e almost iden~ical. angles of friction with an average of 32 deg., 30 min. For materials, either cohesionless of cohesive, which show a characteristic dropping off of the shear stress after the ~aximum has been reached, design should be based on the more conservative value of the angle of friction obtained from the ultimate strength. For designs based on the maximum value, progressive failure and the consequent dropping off of the shearing s~rength would create a serious situation . • Although the results of these series of tests are not entirely consistent nor conclusive, the thickness of the sample ' appears to have an appreciable influence on the value of the an~le of friction, the value tending to smaller for the thick samples than for the thin ones. It also a ppears from a study of IC/ COLUMBIA UNIVERSITY Prof. D. M. Burmister Conclusions (Cont'd) the results that the 0.30 in. samples were too thin for the complete development of the usual thickness of the shearing zone. i Dense i.. Loose 1.05 42'' 45' 32° 25' 0.30 44° 30' 35 ° 30' Mean line all thicknesses 43° 30' 33 ° 30' Voids ratio 0.49 Thickness of SamJ2les a in. 1 0.66 Although the initial voids ratio; initial thickness of the sample, and the voltune changes during shear were measured very carefully, the results still show inconsistencies. These inconsistencies may result fron secondary effects inherent in the direct-shear test method, partly because the size, shape, and tilting of the shear box may affect results, and partly be- cause of the large shearing deformations required to reach the ultimate shearing strength. Because of the prosressive nature of the development of shearing resistance along the shearing plane in a shear box, the state of stress in the shearing plane cannot be known exactly. For these reasons the true an e le of friction is not obtsined, though probably not gre3tly in error. The direct-shear test method is not an entirely satisfactory one for deter.mining the shearing charact-eristics of f; ranular cohesionless materials, and the consistency of results is not as good as desirable. 2.0 COLUMBIA UNIVERSITY Prof. D.M.Burrnister Tes ::;s on 0tta,va Sand l.Maximu.m Shearing Stress State of Sand Voids R2te of Loading Shearing Stre ss : Ton/sc.ft. Normal Load: 'Tons/ s . : . ft. 0.29 0.55 1.06 1.57 2.09 ~i~U:•: • ¢ 43°, 0' 0.36 0.64 1.16 I 1.57 2.10 Loose, Dry 39.8% 0.005"/min 32° 00' 0.22 0.38 0.69 1.34 Dense,Dry 33.3% 0.05"/min 1.03 2. Ultimate Shearing Stress State of Sand Voids Rate of Lo uding /J Ult. Shearing Stress: Ton/so.ft. I': ormal Load : '1 ons/ sq. f't. 0.29 0.55 1.06 1.57 2 .09 34f) 45' 0.21 0.41 0.72 1.09 1.49 Loose, Dry 39.8% 0.005"/min 32° 00' 0.22 0.38 0.69 1.03 1.34 Dense,Dry 3 3. 3o/~ 0.05"/min ZI .... * ~ 1 - --t-,-- ·- -~~t:~ h--:: r·.::.=•i> ' -:·+j--+-,...+'--+--'--1h-'-4--'+-+--+-.,..;...;-'-'-'-+'-'-'---'jl;~-h-'-'-j.....;..._;_;---+..P.~ . • !' .I . r~"L I j 3~~:-T~ - - - .,._..._.._---+ --__,+-,---t--'- ➔-'-'-,.,-.._+-_-, ~: , - - l . ·-: - ·::~~,-: !:: 1 ~- ---~1--:-:-:· -~1, ;~.~~~'i i _. ' ~-· --+-- •- -;-:1 J. - A. L. Davies UNIVERSITY OF MICHIGAN Testing Apparatus For all shear tests this laboratory uses a cylindrical soil specimen with optional provision for applying normal pressures at the ends and a movable section for causing failure in double shear. The two sets of apparatus used differ principally in cross-section~l area of specimen, one being 1 ~ square inches in area or 1.38 inches in diameter and the other 16 square inches in area or 4.52 inches in diameter. These two sizes of cylinders · provide for free lateral expansion of the sand during shearing failure while shearing strains are measured by Federal dials sensitive to 1/1000 of an inch. Testing Procedure It has been observed that shearing deformations involved in such granular soils were relatively small and that failure always occurred abruptly. Therefore, it appeared feasible to conserve time • by eliminating small increments with corresponding small -deformations at the beginning of each test. For Group I, using the small cylinder, shear force was applied in increments to failure with each increment held constant for the 10-minute time interval. Ree.dings of shearingstrain were made at 2-minute intervals to determine whether or not equilibrium had been obtained before the application of the following increment. 24- UNIVERSITY OF MICHIGAN A. L. Davies Testing Procedure (Cont'd) Group II, also employing the small cylinder, differing· from Group I in that the shea ring force was applied at a uniform rate per minute, the rate being not ed for the individual series. Group III, differ- ing from Groups I and II in that use was made of the large cylinder, was otherwise sL;ilar to Group II in that the shear force was applied at a uniform rate. With these so-called rapid shear tests, no con- tinuous record of deformation was possible. However, the ultimate value of strain immediately before. failure was observed and recorded together with the exact shearing force required to produce it. Conclusions A great majority of tests in each series showed good general agreement and appeared to follow consistently the straight line relationship adopted. It might be expected theoretically that these straight lines should all converge at the origin for such a strictly granular material, inasmuch as sand can obviously sustain no shear force without confinement~ This has not been foun d to be the case, however, either in this or similar investiga tions conducted by this and other laboratories. Although the exact source of the divergence cannot be definitely stated, at least a portion of it is felt to be due to experimental inaccuracy in the apparatus while the remainder may possibly be considered as "apparent cohesibn". The effect has been 25 UNIVERSITY OF MICHIGAN A. L. Davies Conclusions (Cont'd) shown as an ,intercept on the vertical axis and has been considered . in determining the angle of internal friction. This cohesion may be produced by the reduction of void content in the test specimen as normal load is applied. Thus in a particular series of tests, all of those specimens were prepared at a definite porosity, the .. application of increasingly higher normal pressures would produce increasingly higher densities until some maximum density controlled by the initial mechanical arrangement of particles is obtained. Further increase in normal presaure would produce no additional consolidation of the specimen and an equilibrum condition would be established. The net result of such an increase in density of specimens during testing would be shear values ~ which increase not only as direct function of the normal load but also as some function of the density change, until the maximum density inherent to the initial arrangement has been obtained. Thereafter the expected direct relationship between normal load and shear should hold. UNIV1RSITY OF MICHIGAN A. L. Davies Tests on Ottavva Sand 1. Summary of Tests using l½ sq. in. cylinder. State of Sand Voids Dense,Dry 33.4% Eq_ual increments Medium,Dry 35.0% Eq_ual incre::i. ents Loose,Dry 38.0% Eq_ual increments Dense,Dry 33. 4?7; Continuous 3#/min. 1 lb./s q_ .in. per min. shearing stre ,,s Group II Medium,Dry 35. 01~ Continuous 3#/min. 1 lb./s q .ir; . per min. shearine; str0ss Loose,Dry 38 .Oib Continuous 3#/min. 1 lb./s q .in. per min. shearing stress Group Group I Loading 2. Summary of Tests usinc 16 sq. in. cylinder. State of Sand Voids Dense,Dry 33.49'; GroupIII Medium,Dry 35.0% Loose,Dry 38.0% ~roup Loading Uniform rate of 3.2 lb./min. or l.o lb./sq. in. sheur stress. Excessive vibration required to produce this dens ity in such a larce sample caused ',rear o f' particles and co11seciuent error in test result s unless new m8.terial was used after ea:ery third tes t . Uniform rate of· 5 lb. /c.i r.. or 1.56 lb./ sq .in. shear stress. E~uul i Lc re2 ents for two t.est. s. Uniform rate of 3.2 lb./:nin. or 1.0 lb./ per s q.in . shear st re sses . Very f lat angle becccuse of cor.:si dation of sand. from loose density in horizontal position. UNIV £GRSITY OF MICHIGAN A. L. Davies Tests on Ottawa Sand Group I State of Sand Voids Rate of Loading Ult. Shearin~ Stress: Tons.Isa. ft. Normal Load: Tons1 s c . ft. ¢ 0.1 0.3 0.5 0.7 1.0 2.0 3.0 Equal InDense,Dry 33-1.i-% crements 52°20 1 at 10 min --- 0.65 0.86 1.22 1.65 2.91 4 . 08 Med., Dry 35.0% do 47°20' --- --- 0.89 1.15 1.39 2.52 3.58 Loose,Dry 38.0% do 42° 40' --- --- 0.70 0.86 0.91 1.68 3.05 Group II State of Sand Voids Rate of Loading Ult. Shearing Stress: Tons/so. ft. NOTI!lal Load: Tons sq. rt. ¢ 0.1 0.3 0.5 0.7 1.0 2.0 3.0 Dense,Dry 33 • '+7~ 3#/min. 55°10' 0 .l+O 0.65 0.90 1.13 1.55 3.02 4.45 :Med., Dry 35.0% do 49° 45' 0.22 0.57 0.88 1.10 1.36 2.61 3.73 Loose,Dry 38.0% do 43° 40' 0.21 0.37 0.57 0.76 1.19 2.14 3.08 Group III State of Sand Rate Voids of Loading I> Ult. Shearing Stress: Tons1so. ft, Norma.L Load; 'l'ons/sq. f't. 0.36 0.7 2 1.44 2.16 ).bO Dense,Dry 33.4% Constant 54° 20' 0.55 0.98 2.05 2.99 5.02 l,1 ed. , Dry 35.0% do 45°10 1 0.50 0.91 1.55 2.37 3.64 Loose,Dry 38.0% do 27°00' 0.45 0.64 0.9 2 1.39 2.04 ' ------~ t.z =~-~ ·· · 3.5 r • --- - .. ----·---·-·-- --- ----- ,- ·~ ,- -------·-· A., ,__ l _ --.>-·.z__ •·. .. . -.'. .- ·P{ ~ • • ---·-··· ·-··--- ····•-- ------· - ------ ------- - -- ----!-- ··- ---- :~ ·___ ; - -- - .' ........ . ··•-·•··- ········--- -··· -----c----·-··•··-··-·· ·-- -·-· ···•-- ·- ---··------- --- ·-·- ------··--.. 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' _M.J CH lGAN.. • - : . ; •· •• -·- ·- ·· -· 1·-· ·-·- ---·-·-· .-- ---- --- - -·-· - - - ··---:···• -····· --·· · ·.·· •• • • -·· · --: ··· ··-- · ••• ··•··.··-· ,-- -· ---, ·- - -·····.· --------'-~---:-·-__ ___Gra_up____.IL__:_ ___ y_·~ --·-,---- ·1--'-----'--'---'---,.--.-.. -· - :-Sf/-··-1)J_._-'-. .__ -· -··· ·· Load__: •• •. ••• ••••• ---- • -···- .. ··· · · ·: Cy .l mde.r . __ ·-· ·----.--: :_____---· j- -Y- --r ---~-- ------. ·-----'----'-------~- :--~.·. R~t~---O/--L :a_o_dmg~ ~-- con_.iinuo.LLS._..~·a _#ijLn.~L2_._ __ _ ' . -;. ------- ,-·- ! - - ' - - - ' ~ -If'.-'-- -~ ···- - - ·--·-·~ ··- ·-· - - - - - · ' ---------- --- _; __ • ·--- --.- - - - bJ---!!""'____..,_...,~-~---------"'!"------------"'""'--------oi,.,-;...._;....____...,._______ --- ---- - ----·-- ··- - - __ __ __ ., ___ ·--·-··· ·- - -- ---- 0 .. 5 : . . .. . . .. .. : . . . . . . . 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F .t ..... . . ••• . . 3'.0 ' -- ·-- - .· -- ---··------·· -- - ----- ------ - - - -- -------------· -- _-- -- - -, - ---- -·-·- - - -- - ' . ·-1---- - - --·--- ·-- ·-· - _ __ _, _ _ _ _ ·- - ·- •-• '- . • •·-- - - -- - -' - - ----- 30 .,. ~ ML . .Clz.LCrA.N ; :_, ·--. -~. . . ..;..U.N.1-V£.i51 _i_y+-: ~ OEL ...... . .. : ' : . • . . ... . . . . - -- ·· - - "· · - · ·· - · - - - - -· · . - .. ••· - · - - · · - · - ·- ··· .......... - · 0 ... . . _ ..-. ------ ·- •···-- __ ... - ----·------- ··-·-···-· ·- ·- ·- ··· -· - - -- ---- ----- --- -------- --- -·-- ---- ---· --- --------------·---- ."·------ - ·--- -· ------ j i tj- .i- ·. . -~ -:'\" ... :.... - -. --·· .. ----__ .:._.. ◊0. .. . -·r&0 ·-- ·--- ~ ~ ~ ~ ~ - ~--. __. .....-.- . ~ ~ ~ • !_. . •-:" - .. ·- •• : . --.. ~ ; . - ·• .......... - ..... ··-·- - - -- - ···· ··· · · · ---;---- .... . . . ,. ..._,_.._. _:·· . ....,. j_ ~ ... • ... . . .... ; o • • • •. h . ;~-s: • -- • - ~_;_~ ·• . ............... . . - .. . ............ --..··- -·--,-------·-----···.·· •·······. . ..... ..·-·· · ···--•-··--·- --..... __._.. _. ··- ..- -- ······ ·- ·.... - ... • ·········- - ·-- ·---·-- -• .•. ··- ·.. .-.. . .... _.....____:· ··--·-DailBLE_.._......Sli.£4RI&.C£ __ ~..I£ s :.L :... . . 1 _•-.-. ... . _____..... __ ..... . . ··· -'-·- -- i . • • ; I • ' • --- --- -·------ ___:______ _ _ - •--- oN_ 0 TTA wA __ QALYa . __ _ ------'--'---'-i>v OJ I --- -· . - . --- ---- -- . . ---- ---,------.J· ---- - - - - ' .. i ~ - - - ~ · . - - - - - - . : - - ;. • ···~ . C . - - - - - ' - ' - - ~ ~ - - - - - - - ~ i•...... i _G_r:_a_vp :. Tll ;..:. :l_L6.:__,.5. fj-.'-JA._. ~_cr-!-1-'i?-de-... · r:~:_ _;_______ii~Lf?_J.~_jz~dmg.:-}!kii_£ a~-&te__: __,___ - --··- •-'---·- ' i : __' _ ___ '. - . : : a ; __ ____ . _ -- -:- -----1---7·--- ··;-:.-;'------·-; -- ' :--- -.;-- --;- -- - ;.-- • ; ! ' - --···· •--·-- ---- ' ' ' : • ___ :---- : ----- -.\ ----~ : 1· - - ' - -........- - ' - - - ' - - - ' - --+-'--' - - + - -; - --;..--:.--'--- - - - ' ' - - -- -' ' ! ·----- :--·--•-i----· ·-· -·· - 1,._ _ _..,._ _ _ _,.._ _ _ _...,_ _ _..._ _..,._ _ _ _ _ _...,_ _ _ _ _ _...,_ _ _ _ _ _..,_ _ _ _ _ _ _ _ _ _ _ _ _,.._ _ _ _ _ _ _ _.,.._ _ _ _ _ _ _ _ _ _ _ _ _-i__..____________i - - - - - -~ 1; 0 1.5 e.o 2. .s 3 ;0 .3,s - . - · - ' - · - - - -·· - ···-·. ! -·--····· ' - ·- - -·•---- -·-·-·--·f---·, _ ..' -. ----- '. ----- : ----' ----- ; --- ~·--'----'--- ·--.-----: ·-- ; 4;0 ! ~~tfQ.ff.._M.I}_,.? . . . • Li:JAb . • •. rotis/·sq~··-;,=-r.__ :....·. . . . :·.·:-·; . •_ _ . .··-·: ·· :_ . ~-'·~ ·:. -: . --. --.. -~·=~~ ----·-~ ·--·"· -·-- ·-·---. -•~ 31 PRINCETON UNIVERSITY Prof. G. P. Tschebotareff Testing Apparatus Three shear bo xes of 60mm x 60mm area were used, mounted on a single frame. The soil samples were about 1/2" thick (count- ing between the extremities of the plate ribs or fins). The clay samples were confined between indented porous carborundum plates. :T he normal load was applied to the upper plates through a piston and loading yoke by means of weights suspended directly to that yoke, ~ithout any leverage being used. The shearing force could be applied at any desired controlled r~te. A water tank connected to the water main and a s ystem of ~ulleys were used for the purpose. small friction losses (about 2%) were taken into account. The The shearing force was applied to the upper movable part of the shear box by means of lugs located on each side of the box in the vertical plane thru the point of application of the normal load. This arrangement eliminated effects of possible tilting, should the shearing force imperfectly coincide with the shearing plane. A rim around the whole shear box per-mitted to entirely submerge the s8.Ill1l)>le and the shear box during the whole duration of the test. PRINCETON UNIVERSITY Prof. G. P. Tschebotareff Tests on Ottawa Sand The shearing of dense sand was found to be accompanied by its expansion. The reverse was the case for loose sand. In addition to the tests of the program, tests were carried out on moist sand to determine the effect of bulking on the shearing resistance. It was found to be reduced by about 15% both for very loose and for very dense Ottawa sand when the sand was moistened by about 6% water before being _placed in the box. There are indica... tioims that if th.e sand is moistened after it is placed in the box, the opposite effect may be observed, that is the shearing resistance may be increased, presumably due to the action of capillary forces. Apart from the prescribed manner of loading, tests were also made in the manner usually adopted in our laboratory, that is at a constant rate of application of the shearing force, equal to 1/20 th of the ultimate load per minute. No difference was obser- ved between the results obtained by the two ways of loading when. dense sand was tested; this was alse the case for loose sand at small normal loads. But loose sand at normal loads over 1.0 tons/ sq.ft. gave higher shearing values when loaded at a constant rate. Presumably the application of the shearing force in large increments may facilitate the breaking do'Wll of the loose structure of the sand followed by premature shearing. 33 Prof. G. P. Tschebotareff PRINCETON mnVERSITY Tests on Ottawa Sand Ultimate Shea ring Stress. State of Sand Porosity Rate of Loading Dense,Dry 31% Constant Rate 0.11 0.28 0.42 0.53 0.73 1.60 2. 4.1 do do Increnent 1/8 Ult. 0.11 0.32 0.46 o.54 !0.s5 1. 1.6o l 2.40 ! : . AverE:,ge 39° 00' 0.11 ; 0.30 0. L!-4 o.53 jo.79 1. 60 i 2.4.1 Ult. Shearing Stress: 'l'ons/so. Ft. Normal Loaa: 'l'ons/Sa.Ytt 0.1 0.3 0 • ,,,~II 0.7 l.O j .::• • Q II 3.0 c/J 1 : i I i Dense, Moist 35% !; Constant Ii j4°40' 0.12 1 . l Rate i I ! I - 0.43 - '' 0.73 i i !I - l - 2.12 i ' ; Loose,Dry 41% Constant Rate do do Incrementj 0.09 0.24 0.38 0. 48 0.77 1.29 1.95 !I 1/8 Ult. - 0.38 - o.66 - 1.85 Avera ge 32°00' I 0.09 0.24 0.38 0.48 0.711.29 1.90 0.09 I i l \ I Loose, M.oist 4 71~ Constant Rate I 30°30'10.0Si i i - 0.33 - 0.59 - 1.78 34- 3S U.S. ENGINEER LABORATORY Fort Peck, Montana Testing Apparatus All tests were made in a Zanesville type of shear machine. The normal stress was applied in each case in a single increment. The first shearing load increment was applied within 2 minutes after the placement of the normal load. ' Each incre~ ment of load was maintained until there was no further horizontal movement of the shear box due to that load. The criterion for this end-point was a movement of 0.001 inch or less in 1 minute of elapsed time. The indication of failure of the sample in shear was a horizontal movement of 0.1 inch or more due to the addition of an increment of load. The shear tests were first made according to the standard method used in the Fort Peck Laboratory which differed from, the A.S.T.M. method only in the stze of the increments of horizontal load used to shear the sample. It will be noted that, in the A.S.T.M. Method, the load increments are equal to or larger than those in the Fort Peck Method for the values of normal stress greater than 0.1 ton/sq. ft. The size of the increments used in the Fort Peck Method are 'those usually used in making shear tests at these several values of normal stress. At the conclusion of the tests make according to the Fort P.eck Method, the values of ultimate shearing resistance thus found were divided by 8 as suggested in the original instructions to give the approximate size of the increment loading to be used in making the test according to the A.S.T.M. Method. 36 U.S. ENGINEER LABORATORY Fort Peck, Montana Conclusions The general effect of using the larger load increments in the A.S.T.M. Method is to produce a lower ultimate shearing strength for the sample than was found in the corresponding test made according to the Fort Peck ivlethod. This effect can be readily seen by comparing the attached plotted curves for the A.S.T.M. Method with those for the Fort Peck Method. 37 U.S. ENGINEERING LABORATORY Fort Peck, Montana Test s on Ottawa Sand Ultimate Shearing Stress. 1. A. S. T. M. Method State of Sand Voids Dense,Dry Rate of Loading ¢ Ult. Shearing Stress: Tons/S o. Ft. Norm.al Load: Tons/So.rt. 0.1 0.3 0.5 0 .·7 1.0 2.0 3.0 3M% Increment 29°10' 0.03 0.10 0.31 0.46 0.59 1.04 1.72 Med., Dry 38 . 4-o/~ do 26°50' 0.02 0.1 2 0.23 0.39 0.55 0.90 1.54 Loose,Dry 40.8% do 24°00 1 !, 0.01 0.1\0.20 0 .3 2 0 .37 0.89 1. 31 2. Fort Peck Method State of Sand Voids Rate of Loading ¢ Ult. Shearin&: Stress· 'Ions/Sq.Ft. Normal Load: Tons/S a . ,'t. 0.1 0.3 0.5 1 0.7 1.0 2.0 3.0 Dense,Dry 36.0% Increment 35°00' 0.04 0.13 0.32 0 .4 5 o.6s 1.26 2o07 Med., Dry 38. 4o/; do 32° 05 t 0.02 0.12 0.30 0.39 0.62 1.17 1.85 Loose,Dry 40.8% do 29° 45' 0.03 0.14 0.31 0.34 0.57,1.12 1.65 Load Increments Size of Horizon.Load Increment: lbs. NoTI:.1.al Load: Tons/Sq.Ft. 0.1 0.3 0.5 0.7 1.0 2.0 3.0 State of Sand Voids A.S,,1 .Jvi. Dense, Dry Medium,Dry Loo se , Dry 36.0% 38. 41~ 40. s5s 2 2 2 5 5 5 7 7 7 10 10 10 15 15 15 35 30 25 40 45 40 Fort Peck Dense, Dry Medium,Dry Loose, Dry 36. O{a 5 5 5 5 5 5 5 5 5 10 10 5 10 10 10 20 20 20 20 20 20 Method 1 ff' 3u. L!-10 0 40. sr; 38 Ithaca, l~ew York Proced;.1re Tests were u t:=.:de with the rn.aterie.l in a very loose an d very dense state, both J.:ry and submerc ed.. }?or t lle series of tests with the material dry, all l)arts of the s h ear bo:t and the sand were oven dried. :?or the submer ged series of tests, water r:,laced in t li e water jacket to produce comple·te suhmerc ence at t h e shear plane. The material was compacted in the shear box by tamping it with a small wooden block and hammer before t lrn normal load was a.ppliedo After the normal load was applied th.e piston was vigor- ously tapped at all corners to vibrate the sand into a more c01hpact mass. Vibratiop. was continued until the vertical dial s11,owed little or no moveme'nt. To place the sand loosely in the box for a dry test, 1·t was carefully poured with a spoon. In the submerged runs, the sand was deposited loosely by allowing it to fall through . the water Tests were made at an approximate rate of horizontal .move.ment of 0.012:~, 0.050 and 0.200 inches per minute. 'l'he rate of horizontal r:~ovement was controlled o:,r moving the horizontal jack at a uniform :rate. Since the pressure bellows deflected very sli ghtly as t he stress was produced, the rate of horizontal movement was not absolutely constant. n ormal loads o:f 0.3, 0.5, 1.0, 2.0, 3.0, 3.5 and 4.0 tons/sq.ft. were used. 4/ Ithaca, New ·:.:ork Testing Ap parat us The tests were rn.ad.e on tlie constant str ain t ype of 1.H rec t s he a r mg c:: i n e. Th is device was ori e:ina ll y desi s n eO. by rrofessor Glennon Gilboy of ::: .I .'r., for t he Zanesville So.il.s La bor &tor y , and described b;,' hi1u in Enc ineeri n:; Kews Record, L'.ay 21, 1936 . The sar1.ple is ;; laced in a s h ear hox, -'1 - " x 4 11 , for the tests described in t 1.,is re1,.,qrt, and the ·oox r, laced in p osition in t h e testing nw.c i1ine. Strain is a pplied a t a con- stant rate to t :ie lower 1-)art of the box by a wheel and j a ck arrnngement, while t h e upp er part is restrained from h ori z ont o.l movement by connections to a yoke bearing a cainst a hy dr aulic bellows. The actual load a l)JJlied to t lle samp le becomes .a function of t h e r esistance offered to movement along t :te h orizontal })lane through t : -i. e sarn:ple between tile lower :£;.?.. rt wl1ic ~1 is moving, and t 1~ e Ul)f er _part whi c l1 is :res t rained. 'r.lt e r;1a cnitude of this l ood is indicated by the heic;ti.t of rise of a r:1an omete r connected t o t he bellows. Provision is a lso made in t h is de- vice fot' t11e a ppl:l.c a tion of a vertical load on t h e s Eunr,le, so . a rranged t hat if t h e sample tends to e xp and durinc t h e tests, it will :not h e ;.: r e-vente d from so doin;;~ , but t i1e ve r tic a l load will J:·e1:1ain constant. 42. Tt;le ·tests i ndi. cate t hs.t for the cort)a ct co nditi on , the s ubmerged LF\terisl has a sli (:)1tly larcer 1.:iaxi .t:n.1n fJ:iction angle t han t h e Dry J\ at eri a l, w:t i le for- tl:ie loose condt ti on the r,·:ucir n..1.D :friction Gri f,).e is a~)l)roxi ma tely t he s cu71e fo:(' both the dry ar:.cl. su'ot:e rc ed • material.. Th e tests also i nd ic &te t ha t the -:..1lti1:1ate f ri cti on angle is ap_proxirnatel y the s ame fox· a ll four conditions of material, in each of the three rates of horizon- 43 Ithaca, New York U.S. ENGINEER OFFICE 'I'ests on Ottawa Sand 1. Maximum Sllearins Stress . State of Voids Sand Rate of L0 2..ding Dense Not 0. 0125",hnin Dry biven 0.05 "/min 0.20 "/min ¢ Maximum Shearin&r Stress: Tons/Sc.Ft. Normal Load: Tons/Sa.Ft. 0.3 0.5 •O.o5; l.O il.32 2.0 3.0 3.5 4.0 ' 0.65 1.25 l.83 0.65 0.86 1.16 1.78 2.00 1.20 1.70 2.10 0.70 0.25 0.20 0.33 0.22 0.37 ! Average 29°20' 0.22 0.35 ' 10.67 0.86 1.20 1.70 2.05 I I ! Dense Not 0. 0125 }!nin Moist given 0.05 "/mjn 0.20 "/min 0.2 2 0.21 0.34 0.24 I 10.72 l 0.60 0.66 . I 1.19!1.~2 i2-16 l; 1. bO I i2. 61 ' T I 1.19 1.88 !2.16 i2.61 l T Average 32° 20' 0. 22 0.34 12. 02 I : !o.66 I • l l I 'I I i j I t Loose Not 0. 012 511,hnin Dry 6 iven 0.05 "/min 0.20 "/min Average I 1.06 1.52 0.96 1.44 0.95 l.M$ \O.h8 0 .11~ 0.25 0.30 10 .49 0 .. 14 10. 51 0.13 26° 40' 0.14 0.25 0.3010.491 ' Loose Not 0. 012 ~'/2:nin ~·/lOist ~iven 0.05 "/min 0.20 "/min Average 0.12 0.15 0.24 0.1.3 25° 40 f 0.13 0.24 'i 10 00 1. ~-8 ~ / ./ I . • II i ' ll . 91 ! ' 11. 91 I I 0.53 c .50 0.50 I o. 51 l 1 l 1.48 Oe94 1.44 1.53 ! 0.94 1.48 j1.98 il. 98 i 44 U.S. ENGINEER 0YFICE Ithaca, Ne~ York Tests on Ottawa Sand 2. Ultimate Shearing Stress lstate of Voids Sand Rate of Loading rp Ultimate Shearing Stress: Tons/so .rt. Normal Load: Tons/ Sq_. }'t. 0.3 0.5 1.0 1. 32 . 2. 0 3.0 3.5 4.0 1 ,,. Dense Not 0. 012;11,hnin Dry given 0.05 "/min 0.20 "/min Average 0.89 1.36 0.15 0.25 0.50 0. 59 0.89 1.35 1.54 0.17 0.48 0.89 1.34 1~63 24° 00 1 . 0.16 0.25 0.49 o. 59 0.89 1.35 1.58 Dense Not 0. 012~'/min Moist jgiven 0.05 "/min 0. 20 "/min • Average Loose Not I O. 0l251'/4nin Dry tiven 0.05 "/min o. 20 "/min ! Average i ··--=·- 0.15 0.24 0.4-5 0.15 24° 40' 0.15 0.24 0.45 0.88 1 l. 4.l 1.35 0.88 1. 38 0.14 0.14 0.45 0.47 o.s6!1.32 0.94 1.33 1.38 24°00' 0.14 0.46 0.90 la34 0.14 0.23 0. l~8 0.12 0.46 1.44 I Loose Not !o.012:3''/min Moist ~iven;o.05 "/min 0.20 "/min Average 25°40' 0.13 0.23 0.47 1.44 • ' 1.88 1·.ss --.,.. ,, .. ,-,_ 45 r ~ ,. :-' . : ~t \L~ ........-'___, : :!. ::.:r::•: . l •. ---i------ - ' "f'.,..., ·, . . , . -'-. ' ,. .. I- .,_, ' - , •r'--'t~ ::J~f:Sj,c~/: ~'.-c .__ -,i -) ~~ 1 : l ~t.-+-,-~---'4- 7· ·: • 1·.:~ ' -71'"--~:--r-·. ..., •• •--.. . . . • ~ .: • • .. • .I : _:..j . 1 1. "'- -+ - - ~ -- ·I· , . , ,1:ill 1 I,{: '. ~:~;1--J -----~ :__ (\".)~ -;-:: . !. l. 1. . : :..+-:-- --r-- ; i------ --1--·➔-·•--t·-·---- r - · - -·-r·--n1~·~:;~ ~ ~ t ~ <- ~ •-. ~ .• t~' ::. j __, ' :_ -~-1 >J· l : :~ ·; . 1: .. .'.I. • : :.: . J-· T' , !·. '. ···: . ' > ·: .;.·FD ' _;_ ·ITT_,_ ._~,:--1-,- :~, . : , , . 1 . ·-_ .:.. ~-,~:~0 :-:-·1: · ·-i 1 , . . . • , .. :i. , c,. , ~ -?[ ' :,\"_ .;: ·.·• j :,J1t . ' - ,..,..,.,- , ,- - : ,- i;-,-- -:r:---:TiT -;-,-r.,,·1 , ..t .,~.II '-', , . ,.,r, -, j-,'•· · •f ji~ ! • I . : !. : I, 1 : ; -:-:- ; -_; tt-- .,--T ·71-:----·.T--:-l+:-:·· -:-:--;: 4·-·:r f-~---t---- -:- ... ·1 : ·: \ : l;_ t •. i- I ~-+ -·:1· ' : ·r: : :· ,-4. ; :·L: ·•; ::'. ·:. l ·: 1-, .' :J;-::::-r~T·-;- 7 :1~:!J:--:ff-fl l-;-;_-:r:--T-T-- ---··t~:1 ~fuITT:;J--· 1•-: :1~~-.::~f~~~ +·_--· ··-1-:·:···j : r~rtn:·~~nn: J;: ·· ::r7/,fJ 1: •:-1- ~f~ ' tt:;+;1:;; :: 1 ,- ,-, "i : -+ '-~·+_ -_ ~:--j•l,J•:f---+-::...-...,b----.:...r-4'!-_ : ....:.... :_-,.-,;,.;~:~:~:'°:__:: ; ~~c~~~+..;..f--:....J..:...::_-'-,....--c-+-:-'~-- ,._...,___ '.'tr:..,..~-ta- -4.,-,,µ,>t-_:1n-r:------r-:--:-"'"',~ ...,..+ ~ -"----'--+ --, •• U.S. DEPT. OF INTERIOR Washington, n.c. Grain Size .Analysis of Ottawa Sand The specifications required sand that would pass #20 and be retained on #30 seives respectively. The Engineering Laboratory uses #16 and #32 seives because these more closely ap.pro:x:imate the upper and lower boundaries of "coarse sand" according to the National Park Service grain size identification. lt is believ.e d that the material meets the specifications even though the specified seives were not used. The sample was first thoroughly oyen dried at 105 C following which it was placed in the Rotap. After 5 mins. the sieves were removed and material in each seive brushed lightly to remove any finer particles that might remain. The portion on each seive was then oven dried, cooled, and weighed. The initial and final total sample weights checked within less than 0.01%. Testing Apparatus The shear apparatus of the Engineering Laboratory differs in some respects from the apparatus used by M.I.T., the Corps of Engineers, and others. The following is a brief description: Size of sample - 2.5 ins. in diam., 1 in. in thickness Shear Box - Upper section rigidly supported on base. Lower section moves on ball bearings. Wa shington, D. C. U. S. D.EP'I·. OF I N'l'ERIOR Testin 0 Apparatus (Cont' d ) Bearing - Two tool steel raceways attache d to base; both V groove. Raceways on bottom of mov:::. ble section of box , V groove on one side, plane on t h ,J other. · Normal Load - Fixed increments supported by yoke and saddle. Yoke and s a ddle form first increment. Load transmitted to sample from yoke by means of ball bearing and bearing plate. Horizontal Load - 1.5 cu. ft. contBiner, water load. Container counte r balcmce d by wei cht suspended from rear of moveable section of' shear box. Increments corrected for mechanical losses in t he machine. The various elements were de si gned to accomplish certain results. First, the bottom section of the box was made moveable instead of the top section as is more usual in order to eliminate all loads from 'i,he sample with the exce1,. tion of the. t due to one half the sa.,nple t hickness, and to elimina t e t he ne c essity of adjustins the s pa ce be ~we en sec ::. ions after the s c. mple i s in plac e . The conta iner and water for the horizontal loading wa s used for sever al re a sons. 'I'he f irst was reducti on of cos t of the device. Another is the elimination of the possibility of setting up excess loads due either to dropping fixed increments or res t ing on a beam. Since t l1 e increment f lovrn by a siphon from a reservoir set 4-9 U. S. DEPT. O:B, IN'fi1UOR Washington, D. C. Testing Apparatus (Cont'd) on a sc ale the lciad can be applied by a single operator who need not loolt away from the horizontal dial duril').g the loading since he can obtain the net from the scale after the load is applied. The increment is usually determined by the rat e of dial movement ·.vhich is set up rather than by definite weight intervuls. Moreover, the apparatus permits continuous loading at any reasonable rate desired. The s1:U11ple is permitted to come to complete rest after normal loads are applied. · When horizont&l load increments are applied the sm11ple is permitted to stand until movement of the dial is less than 0.00025 ins. in two or three minutes. Actual shearing load is determined from the stress-s t rain plotting. 6U U. S. DEPT. OJ!' INTERIOR Washington, D. C. Tests on Ottawa Sand Ultimate or :Maximum Shearing Stress .,· State of Sand Voids Dense Dry 33-4% Increment 50°00' 0.32 0.60 0.88 1.17 l .~.6 Medium 35.0% do 44°20' 0.24 0.47 0.72 0.97 1.17 37-3% do 36° 00' 0.21 0.38 0.5 2 0.70 0.90 Dry Loose Dry Rate of Loa ding ¢ Shearing Stress: Tons/Sa. Ft. Normal Load: ,. ,. , ons; c::.q u-+ 0. 234 0.476 0.718 0.960 1.ao3 1.445 1.687 l. \...J •.L' V • 1.01 1.25