Hydrological response to rainfall infiltration of back filled retaining wall: a case from Laiwushan back-filled retaining wall

Abstract

Several cracks were found to occur on the slope face of the Laiwushan retaining wall.In order to understand the mechanism of deformation and failure mechanism,automatic monitoring instruments,including piezometers,tensiometers,moisture probes and in-place inclinometers were installed at the top of fill slope.The following findings can be observed based on the monitoring data of piezometers,moisture probes and tensiometers:rainfall infiltration has little influence on the fluctuation of the groundwater table,possibly because the groundwater table was deep;the response of pore pressure and volumetric water content at various depths in the fill was delayed,depending on the soil depth.The rainwater can infiltrate into a depth of over 3m,and a perched water table can be observed at the depth of 3m,resulting in reduction in shear strength of soil and potential shallow failure. 深圳賴屋山的一擋墻表面出現數條裂縫,為了深入研究其變形破壞機制,在擋墻背后填土區布置自動監測儀器,主要包括滲壓計、張力計與水分計及固定式測斜儀。通過對滲壓計、張力計和水分計的監測數據分析表明:填土內地下水位埋深大,降雨對其影響小;土體中孔隙壓力和體積含水量對強降雨響應隨著埋深存在不同程度的滯后性,強降雨入滲深度大于3m,并且在3m處形成瞬態飽和地下水,抗剪強度降低,易于引起邊坡的淺層變形破壞。