Effect of trees on suction in soil slopes

• Main Author: Chen, Xingyu
• Other Authors: Leong Eng Choon
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Civil engineering::Geotechnical
• Online Access: http://hdl.handle.net/10356/76318
• Institution: Nanyang Technological University

Most residual slopes have deep groundwater table, where the soil above the ground water table is unsaturated. However, the high-intensity and long duration rainfall can cause the soil to become fully saturated and slope failure may occur. Matric suction plays an important role in the shear strength of the unsaturated soil as the negative pore water pressure contributes additional shear strength to the soil. This study carried out a field monitoring programme on a residual soil slope where two rain trees are on the crest of the slope. Suction was measured at four different rows, five different locations and three different depths using Quick Draw tensiometers. The results during the dry period show the point at 20 cm depth nearest to the tree experienced the highest suction and the suction decreases as depth increases or the distance from the increases. During the rain period, the effect of tree on suction decreases significantly at crest of the slope and the effect of the tree was not seen at row 3 and row 4.