Uji Triaksial Tidak Terkonsolidasi - Tidak Terdrainasi dan Uji Tekan Bebas pada Tanah di Lokasi PDAM Tirtanadi Medan Marelan dan Prediksi Balik dengan Metode Elemen Hingga

Abstract

To determine the shift parameters of a particular type of soil, triaxial and free press tests are carried out as common experiment. In this research, the triaxial test used Unconsolidated Undrained Test (UV-Test). Free press test is an undirectional press test, with no restraint from the side (lateral) of cylindrical soil samples in the original condition. The data generated from this test were the maximum compressive stress data of testing ground The research was aimed to determine comparison between triaxial test result with unconsolidated undrained/VU Test and unconfined comprehension test on soil samples conducted in laboratory. Then, returned prediction was conducted on laboratory test results using finite element method, with the pattern of MohrColoumb and soft soil model. The laboratory triaxial results of UU and Unconfined Comprehension Test showed huge disparity between tension and strain when failure occurred, that is value of Unconsolidated Undrained Triaxial failure tension > unconfined compression test and value of Unconsolidated Undrained Trixial strain < unconfined compression test. The results of returned prediction on modelling with plaxis Mohr-Coloumb and soft soil model showed value of tension when failure occurred was almost similar to laboratory test result. There were considerable differences in the strain. Based on Unconsolidated failed Triaxial Test-I ( a3 = 50 kN/m2), the value of deviator tension when collapsed occurred was Mohr-Coloumb 57.400 kN/m2 , Soft-Soil 55.45 kN/m2 whereas laboratory results was 59.00 kN/m2 and value of strain was Mohr-Coloumb 0.028, Soft-Soil was 0.14 whereas the laboratory result was 0. 09. Based on unconfined comprehension test it was obtained value of compressive strength when failed occurred for Mohr-Coloumb 23.830 kN/m2 , Soft-Soil 23.829 kN/m2 whereas laboratory result was 24.30 kN/m2 and value of strain of Mohr-Coloumb 0. 096, Soft-Soil 0. 046 whereas the laboratory result was 0.14. Soil taken as a test material was classified into sand with clay.