Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 7 2021 09 23 Numerical and Experimental Investigation of Optimal Soil Improvement with Lime and Cement and Its Impact on Reduction of Settlement in West Tehran Wastewater Treatment Plant Numerical and Experimental Investigation of Optimal Soil Improvement with Lime and Cement and Its Impact on Reduction of Settlement in West Tehran Wastewater Treatment Plant 2937 2956 4131 10.22060/ceej.2020.17574.6607 FA Masoud Zabihi-Samani Iran University of Science and Technology: Tehran, Tehran 0000-0002-1330-165X Seyed Mostafa Daryabari Master of Science Parand Branch, Islamic Azad University, Parand, Iran. Seyed Aboulfazl Daryabari Master of Science, Tarbiat Modares University Alireza Mirhabibi Islamic Azad University,Parand Branch Journal Article 2019 12 22 In this research, lime and cement additives were used to stabilize clay and therefore to reduce the settlement in raft foundations. Lime and cement were mixed with clay and the effect of the use of these two additives on the stabilization of fine clay soil in the laboratory was investigated. Soil samples in normal state and combination with different percentages of lime and cement equal to 3%, 6%, and 8% dry weight of soil for laboratory tests including Atterberg limits test, grading test, standard compaction test, uniaxial compressive strength test, and California bearing ratio test. Also, the consolidated undrained triaxial compression strength test (CU) and direct shear tests were used. The results showed a decrease in the plasticity and maximum dry density of soil and an increase in optimum moisture content, compressive strength, and also the California bearing ratio of clay by adding these two materials. The cohesion and internal friction angle obtained from consolidated undrained triaxial compression strength tests (CU) and direct shear tests increase with increment of cement and lime percentages. After laboratory tests, the effects of the use of soil improvement with depths of 1m, 2m, 4m, 6m, 8m, and 10m using Plaxis2D software suggests that as the depth of improvement increases, the number of settlement decreases, which is a lot different from that of the plate loading test before improvement while the difference between the results obtained from Plaxis2D and plate loading test after improvement is negligible. In this research, lime and cement additives were used to stabilize clay and therefore to reduce the settlement in raft foundations. Lime and cement were mixed with clay and the effect of the use of these two additives on the stabilization of fine clay soil in the laboratory was investigated. Soil samples in normal state and combination with different percentages of lime and cement equal to 3%, 6%, and 8% dry weight of soil for laboratory tests including Atterberg limits test, grading test, standard compaction test, uniaxial compressive strength test, and California bearing ratio test. Also, the consolidated undrained triaxial compression strength test (CU) and direct shear tests were used. The results showed a decrease in the plasticity and maximum dry density of soil and an increase in optimum moisture content, compressive strength, and also the California bearing ratio of clay by adding these two materials. The cohesion and internal friction angle obtained from consolidated undrained triaxial compression strength tests (CU) and direct shear tests increase with increment of cement and lime percentages. After laboratory tests, the effects of the use of soil improvement with depths of 1m, 2m, 4m, 6m, 8m, and 10m using Plaxis2D software suggests that as the depth of improvement increases, the number of settlement decreases, which is a lot different from that of the plate loading test before improvement while the difference between the results obtained from Plaxis2D and plate loading test after improvement is negligible.

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