Test and Analysis of Deformation Characteristics of Deep Foundation Pit in Residual Soil Under Rainfall

doi:10.16183/j.cnki.jsjtu.2019.012

Abstract

Abstract:

Residual soil has a poor water stability, whose strength varies with the changes of saturation and deformation. To study the deformation response of foundation pit in deep residual soil affected by rainfall, the deformation of retaining pile and ground surface settlement outside the pit was monitored based on a deep residual soil foundation pit project in Xiamen. Combining the excavation steps with rainfall data, the influence of the strength weakness of residual soil caused by rainfall on the deformation of retaining piles and soil was discussed. The results show that the deformation of retaining piles and soil settlements remains stable during rainfall, and increases slowly in the stage of drainage. However, as the excavation continues after drainage, the deformation increases significantly. The maximum lateral deformation affected by rainfall is about 1.5 times of that without rainfall. The influence range of the ground surface settlement on excavation depth increases from 1.5 to 2.5 times due to rainfall. The results have a certain reference significance for the engineering application of residual soil foundation pit affected by rainfall.

Key words: foundation pit deformation, ground surface settlement, residual soil, rainfall

CLC Number:

TU473.2

XIAO Zhaoyun, LI Mingguang, WANG Dafa, CHEN Jinjian. Test and Analysis of Deformation Characteristics of Deep Foundation Pit in Residual Soil Under Rainfall[J]. Journal of Shanghai Jiaotong University, 2020, 54(8): 873-880.

Figures/Tables 12

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土层名称	γ/(kN·m^-3)	c/kPa	φ/(°)	E_s/MPa	σ₀/kPa	ν
杂填土	18.0	12	15	5.0	100	0.30
粉质黏土	19.0	30	13	5.5	200	0.28
残积砾质黏性土	19.4	25	22	6.0	230	0.26
全风化花岗岩	18.9	26	25	6.5	280	0.24
砂砾状强风化花岗岩	21.0	30	27	10.0	400	0.24
块状强风化花岗岩	22.0	50	28	—	800	0.22