Influence of Height-Width Ratio of Water Stop Defect on Water and Sand Leakage in Foundation Pit of Water-Rich Sandy Layer
In water-rich sand layer,the support of foundation pits often suffers from water and soil loss due to the water stop defect,which will lead to surface settlement.At present,further research is needed to be focused on the disaster of water and sand leakage of foundation pit caused by water stop defect.Taking the sand of a subway foundation pit near Ganjiang River in Nanchang City,Jiangxi Province as an example,this work considered the height-width ratio of water stop defect in the foundation pit,and investigated the evolution process of water and sand leakage disaster through visual indoor experimental device.The PFC3D software was adopted for simulation and comparative analysis to explore the change process of geometric morphology and microscopic parameters.Results show that the larger the height-width ratio of water stop defect is,the faster the water and sand leakage develops.The greater the particle loss rate is,the larger the erosion range of sand particles is.With the height-width ratio increasing from 1:1 to 2:1,the number of particle loss increases from 2673 to 40127,and the formation time of soil arch develops from 600000 steps to failure to form soil arch,with the presence of critical height and width value when soil arch occurs.The fluctuation of coordination number in the process of numerical simulation shows that during the process of water and sand leakage,a fierce collision occurred between fine particles and coarse particle skeleton.The water and soil loss leads to the increase of porosity and permeability coefficient,which further aggravates the phenomenon of water and sand leakage.
foundation pitheight-width ratio of water stop defectwater-rich sandy layerwater and sand leakagePFC3D software
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