Rituparna Das, Kankana Majhi, Subhadip Mukherjee, Subhadip Das, Subir Shil

Transcription

1 Internatinal Jurnal f Scientific & Engineering Research, Vlume 7, Issue 4, April ENHANCEMENT OF SHEAR STRENGTH PROPERTIES AND STABILITY OF SOIL BY USAGE OF PLASTIC STRIPS Rituparna Das, Kankana Majhi, Subhadip Mukherjee, Subhadip Das, Subir Shil ABSTRACT - In a cuntry like India where the natality rate is 3 per secnd, availability f prper land fr shelter and clean drinking water is a bizarre demand and hence ecnmic methds are mre acceptable than healthier methds which in turn leads t excessive use f chemically manufactured plastics fr all kind f day t day activities. The undesirable effects f plastic use which cnsecutively leads t pllutin which must be eliminated r at least reduced. Rapid imprvements in the engineering wrld have influenced a lifestyle f human beings in utmst extends but day t day activities f mankind are augmenting risk in the envirnment in the same prprtin. Plastic wastes have becme ne f the majr prblems fr the wrld. The harmful gas which is being prduced during manufacturing and burning f plastics leads t carcingenic pllutants. S, effective cnsumptin f plastic waste in engineering applicatin has becme ne f the challenging jbs fr envirnmental, getechnical engineers. The main bjective f this study is t investigate the use f waste fiber materials in getechnical applicatins and t evaluate the effects f waste plyprpylene fibers n shear strength f unsaturated sil by carrying ut direct shear tests and uncnfined cmpressin tests n tw different sil samples. The results btained are cmpared fr the tw samples and inferences are drawn twards the usability and effectiveness f fiber reinfrcement as a replacement fr deep fundatin r raft fundatin, as a cst effective apprach. Index terms: effectiveness, Fiber Reinfrcement, Direct Shear Test, Plastic Waste, Shear Strength, Tri-axial Test, unsaturated sil 1. INTRODUCTION SOIL frms the integral matrix f land segregated in a Fr any land-based structure, the fundatin is very imprtant and has t be strng t supprt the entire structure. In rder fr the number f layers. Sil arund the wrld are f varius fundatin t be strng, the sil arund it plays a very critical rle. cmpsitins and has varied physical, chemical and S, t wrk with sils, we need t have prper knwledge abut physilgical prperties which invariably cmes int actin their prperties and factrs which affect their behavir. The prcess when sil is subjected t external lads r pressure. Sme f f sil stabilizatin helps t achieve the required prperties in a sil needed fr the cnstructin wrk. them may respnd psitively frm engineering pint f view and sme may nt. Psitive respnse will be cnsidered nly Frm the beginning f cnstructin wrk, the necessity f enhancing when the mass is stable against nrmal and shear failures sil prperties has cme t the light. Ancient civilizatins f the under lads. Due t scarcity f land in the present day the Chinese, Rmans and Incas utilized varius methds t imprve sil weak lands cannt be eliminated and must be put t use and strength etc., sme f these methds were s effective that their buildings and rads still exist. In India, the mdern era f sil hence the sil has t made capable enugh t bear the stabilizatin began in early 197 s, with a general shrtage f incmings lads and external pressure. Thus stabilizatin f petrleum and aggregates, it became necessary fr the engineers t sil is an imprtant task t be dne befre a cnstructin is lk at means t imprve sil ther than replacing the pr sil at started. Fr this purpse, a number f research, materials and the building site. Sil stabilizatin was used but due t the use f equipment, it is emerging as a ppular and cst-effective bslete methds and als due t the absence f prper methd fr sil imprvement. technique, sil stabilizatin lst favr. In recent times, with the increase in the demand fr infrastructure, raw materials and fuel, sil stabilizatin has started t take a new shape. With the availability f better research, materials and Rituparna Das, Prtemp Lecturer,Civil Engineering Department, equipment, it is emerging as a ppular and cst-effective Camellia Institute Of Technlgy,India.Cntact N.: methd fr sil imprvement. Kankana maji, Prtemp Lecturer, Civil Engineering Depertment, Camellia Institute f Technlgy, India, Cntact n.: Subhadip Mukherjee, persuing B-Tech degree in Civil Engineering frm Camellia Institute g Engineering, India, Cntact n.: Subhadip Das, persuing B-Tech degree in Civil Engineering Department frm Camellia Institute f Engineering, India, Cntact 216 n.: Subir Shil, persuing B-Tech degree in Civil Engineering Department frm Camellia Institute f Engineering, India, Cntact n.: Sil stabilizatin is a cllective term fr any physical, chemical, r bilgical methd r any cmbinatin f such methds emplyed t imprve certain prperties f natural

2 Internatinal Jurnal f Scientific & Engineering Research, Vlume 7, Issue 4, April sil t make it serve adequately an intended engineering purpse. The basic principles f sil stabilizatin are: Evaluating the prperties f given sil. Deciding the lacking prperty f sil and chse effective and ecnmical methd f sil stabilizatin. Designing the stabilized sil mix fr intended stability and durability values. Here, in this prject, sil stabilizatin has been dne with the help f randmly distributed plyprpylene fibers. The imprvement in the shear strength parameters has been stressed upn and cmparative studies have been carried ut using different methds f shear resistance measurement. 2. TEST PROCEDURE Tw substantial quantity f sil samples has been cllected frm KIT campus cnstructin site lcated at park circus and C.I.T campus at Madhyamgram respectively. Even befre we check fr the shear strength f the sil sample certain rutine tests has t be carried ut in rder t classify the type f sil and its varius getechnical prperties. Once the rutine tests has been cnducted each sil sample was divided int 4 main parts and the sil samples are cmpacted at their respective maximum dry density (MDD) and ptimum misture cntent (OMC), crrespnding t the standard prctr cmpactin tests. Cntent f fiber in the sils is herein decided by the equatin (pf=wf /W) where, pf= 216 rati f fiber cntent, Wf = weight f the fiber, W = weight f the air-dried sil. The different values f plastic cntent adpted in the present study fr the percentage f fiber reinfrcement are,.5,.15, and.25. The fibers were first mixed int the air-dried sil in small increments by hand, making sure that all the fibers were mixed thrughly, s that a fairly hmgenus mixture is btained, and then the required water was added Direct Shear Test: The sil samples s prepared were placed in the shear mld f vlume 9cm 3 t carry ut the test. This test is used t find ut the chesin (c) and the angle f internal frictin (φ) f the sil, these are the sil shear strength parameters. The shear strength is ne f the mst imprtant sil prperties and it is required whenever any structure depends n the sil shearing resistance. The test is cnducted by putting the sil at OMC and MDD inside the shear bx which is made up f tw independent parts. A cnstant nrmal lad (ς) is applied t btain ne value f c and φ. The prving ring attached measures the lad applied is f sensitivity 1 divisin = 3.82 N. Hrizntal lad (shearing lad) is increased at a cnstant rate and is applied till the failure pint is reached. This lad when divided with the area gives the shear strength τ fr that particular nrmal lad. The equatin ges as fllws: (τ = c + ς * tan φ) After repeating the experiment fr different nrmal lads (ς) we btain a plt which nrmalized t a straight line with slpe equal t angle f internal frictin (φ) and intercept equal t the chesin (c). S. N. SAMPLE 1 (Park Circus) Value 1 Liquid Limit 28 2 Plasticity Index Specific Gravity Cefficient f unifrmity (Cu) Cefficient f Curvature (Cc).37 6 Optimum Misture Cntent 14 % 7 Maximum Dry Density Classificatin f sil ML 9 ML= Inrganic silt with lw plasticity SAMPLE 2 (Madhyamgram) S. N. Prperty f Sil Value 1 Liquid Limit Plasticity Index Specific Gravity Cefficient f unifrmity (Cu) Cefficient f Curvature (Cc).39 6 Optimum Misture Cntent 18 7 Maximum Dry Density Classificatin f sil CL 9 CL= Clay with lw plasticity 2.2. Tri axial Test: After the preparatin f remlded samples in cylindrical shapes the test is cnducted till the specimen fails in shear. The specimen is nt subjected t any hrizntal cnfined frces. The uncnslidated, undrained shear strength f uncnfined sil is determined in this experiment. The uncnfined cmpressive strength (qu) is the cmpressive stress at which the uncnfined cylindrical sil sample fails under simple cmpressive test. The experimental setup cnstitutes f the cmpressin device and dial gauges fr lad and defrmatin measurement respectively. The lad was taken fr different readings f strain dial gauge starting frm ε =.5 and increasing by.5 at each step. The crrected crss-sectinal (A ) area was calculated by dividing the area by (1- ε) and then the cmpressive stress fr each step was calculated by dividing the lad with the crrected area as per fllwing equatins: qu= lad/crrected area (A ) qu- cmpressive stress A = crss-sectinal area/ (1- ε) The prving ring used fr lad measurement is f sensitivity 1 divisin =1.16N

3 Internatinal Jurnal f Scientific & Engineering Research, Vlume 7, Issue 4, April Sample 2 3. RESULTS & DISCUSSIONS The entire test has been cnducted in 2 parts. Each f the sample (maintaining the unifrmity f getechnical prperties) has been subjected t direct shear test and triaxial test cnsecutively and the results btained are pltted in graphs in rder t cmpare the different increments and decrements f the shear strength f reinfrced sil mass with plastic. Shear stress (kg/cm2) fr different plastic reinfrcement %.5%.15%.25% Direct Shear Test: Sample 1 Nrmal Stress (kg/cm 2 ) Shear stress (kg/cm 2 ) fr different plastic reinfrcement %.5%.15%.25% Shear stress in kg/m Nrmal stress in kg/cm2.% plastic.5% plastic.15% plastic.25% plastic Results frm figure 2 Reinfrcements with plastic variatin.%.5%.15%.2% fig1: representain f shear stress t crrespnding nrmal stress at different reinfrcements Nrmal Sress in kg/cm 2 Shear Stress in kg/cm2 Chesin ( c) kg/cm2 Angle f frictin(φ) fig 2: representain f shear test t crrespnding nrmal stress atdifferent reinfrcements Frm the abve study we find the increments achieved in chesin, angle f frictin and shear stress. Results frm figure 1 Chesin ( c) kg/cm2 Angle f frictin(φ).% plastic.5% plastic.15% plastic.25% plastic Reinfrcements with plastic variatin.%.5%.15%.2% Reinfrce ment % Increments in c and φ value Sample 1 Sample 2 c φ c φ % % % % %.5% 1%.8% 34.7% 4.31%.15% 4.8%.31% 6.9% 3.2 %.25% 3.73%.47% 7.7% 6.84% Hence we can say fr sample 1 chesin value increases frm.325 kg/cm2 t.3887 kg/cm2, a net 19.6%. The angle f internal frictin increases frm t degrees, a net 216

4 Internatinal Jurnal f Scientific & Engineering Research, Vlume 7, Issue 4, April %. The increment in shear strength f sil due t Axial Strain Axial stress (kg/cm2) fr different plastic reinfrcement %.5%.15%.25% reinfrcement is marginal. In sample 2 the chesin value increases frm.3513 kg/cm2 Values f max UCS in (MPa) Reinfrcements with plastic variatin exhibiting the increment.%.5%.15%.25% Increment in % 11.68% 1.36%.62% strength t.5375 kg/cm2, a net 53.%. The angle f internal frictin increases frm t 32 degrees, a net 15.2% The increment graph fr φ shws a variatin in slpe- alternate rise and fall. The increment in shear strength f sil due t reinfrcement is substantial. Axial Stress IN Mpa fig 3:plt f stress vs strains t determinatin f UCS maximum values Axial Srain in mm.% plastic.5% plastic.15% plastic.25% plastic 3.2. Tri-Axial Test Sample Sample Axial Strain Axial stress (kg/cm 2 ) fr different plastic reinfrcement %.5%.15%.25%

5 Internatinal Jurnal f Scientific & Engineering Research, Vlume 7, Issue 4, April Axial Stress in MPa Values f max UCS in (MPa) Increment in strength fig 4:plt f stress vs strain t determine the maximum values f UCS Axial strain in mm.% plastic.5% plastic Hence frm the resultants f fig 3 and fig 4 it can easily be deduced that fr sample 1 UCS value increases frm.643 MPa t.562 MPa, a net 14.4% and fr sample 2 UCS value increases frm.692 MPa t.137 MPa, a net 49.8%. (illustrated abve). The increase in the internal angle f frictin (φ) was fund t be.8%,.31% and. 47% respectively (illustrated in figure- 27). Since the net increase in the values f c and φ were bserved t be 19.6%, frm.325 kg/cm2 t.3887 kg/cm2 and 1.59%, frm t degrees respectively, fr such a sil, randmly distributed plyprpylene fiber reinfrcement is nt recmmended The results frm the UCS test fr sil sample- 1 are als similar, fr reinfrcements f.5%,.15% and.25%, the increase in uncnfined cmpressive strength frm the initial value are 11.68%, 1.26% and.62% respectively (illustrated). This increment is nt substantial and applying it fr sils similar t sil sample- 1 is nt effective..15% plastic.25% plastic 4.3. The shear strength parameters f sil sample- 2 were determined by direct shear test. Figure- 26 illustrates that the increase in the value f chesin fr fiber reinfrcement f.5%,.15% and.25% are 34.7%, 6.9% and 7.7% respectively. It has been seen that the increase in the internal angle f frictin (φ) was fund t be.8%,.31% and. 47% respectively. Thus, a net increase in the values f c and φ were bserved t be 53%, frm.3513 kg/cm2 t.5375 kg/cm2 and 15.2%, frm t 32 degrees. Therefre, the Reinfrcements with plastic use f plyprpylene fiber as reinfrcement fr sils like sil variatin exhibiting the increment sample- 2 is recmmended..%.5%.15%.25% On cmparing the results frm UCS test f sil sample- % 35.84% 2.87% 7.46% 2, it is fund that the values f uncnfined cmpressive strength shw a net increment f 49.8% frm.692 MPa t.137 MPa. This als supprts the previus cnclusin that use f plyprpylene fibers fr reinfrcing sils like sil sample- 2 is recmmended Overall it can be cncluded that fiber reinfrced sil can be cnsidered t be gd grund imprvement technique specially in engineering prjects n weak sils mstly in clayey type sils where it can act as a substitute t deep/raft fundatins, reducing the cst as well as energy. 4. CONCLUSION On the basis f present experimental study, the fllwing cnclusins are drawn: 4.1. Based n direct shear test n sil sample- 1, with fiber reinfrcement f.5%,.15% and.25%, the increase in chesin was fund t be 1%, 4.8% and 3.73% respectively 5. REFERENCES a) S. A. Naeini and S. M. Sadjadi,(28), Effect f Waste Plymer Materials n Shear Strength f Unsaturated Clays, EJGE Jurnal, Vl 13, Bund k,(1-12). 216

6 Internatinal Jurnal f Scientific & Engineering Research, Vlume 7, Issue 4, April b) Yetimglu, T., Inanir, M., Inanir, O.E., 25. A study n bearing capacity f randmly distributed fiber-reinfrced sand fills verlying sft clay. Getextiles and Gemembranes 23 (2), c) Chasheng Tang, Bin Shi, Wei Ga, Fengjun Chen, Yi Cai, 26. Strength and mechanical prperties f ply prpylene fibresfiber reinfrced and cement stabilized clayey sil. Getextiles and Gemembranes 25 (27) d) Mahmd R. Abdi, Ali Parsapajuh, and Mhammad A. Arjmand,(28), Effects f Randm Fiber Inclusin n Cnslidatin, Hydraulic Cnductivity, Swelling, Shrinkage Limit and Desiccatin Cracking f Clays, Internatinal Jurnal f Civil Engineering, Vl. 6, N. 4, ( ). e) Cnsli, N. C., Priett, P. D. M. and Ulbrich, L. A. (1999). The behavir f a fibre-reinfrced cemented sil. Grund Imprvement, Lndn, 3(1), f) IS 272 part (xiii)