波浪侵蚀诱发碎石土岸坡变形的模拟试验研究

Simulation and test study on wave-induced erosion and deformation of gravelly soil bank slope

波浪对岸坡的侵蚀不仅造成水土流失,甚至诱发塌岸和滑坡灾害发生。为探究波浪侵蚀对碎石土岸坡变形的影响,开展了波浪侵蚀岸坡的水槽试验,采用PIV技术对不同侵蚀阶段的岸坡位移进行定量处理,并利用ABAQUS中的“生死单元”功能模拟实现不同阶段的岸坡前缘侵蚀,分析侵蚀进程对岸坡应力场和位移场的影响。研究结果表明:岸坡坡度越大、碎石含量越少,岸坡侵蚀速率越快;水槽试验和数值模拟均表明岸坡后部变形相较于前部变形小,且存在滞后现象,呈现牵引式变形的特征;侵蚀改变了岸坡前缘形态,导致上部土体产生卸荷效应,是岸坡变形的内在原因。

Wave-induced erosion on bank slope not only causes water and soil loss,but also induces bank collapse and landslide disasters.In order to explore the influence of wave-induced erosion on the deformation of gravelly soil bank slope,a set of tests was carried out in a wave flume,and the PIV technology was used to quantitatively treat the displacement of the bank slope at different erosion stages,the"life-death unit"function of ABAQUS was adopted to simulate the front erosion of the bank slope.The influence of the erosion processes on the stress and displacement fields of the bank slope was further analyzed.The results show that the greater the slope gradient and the less the gravel content,the faster the erosion rate of the bank slope.The deformation at the rear of the bank slope is smaller than and lags behind that at the front,which showing the characteristics of tractive deformation.Erosion changes the front shape of the bank slope and leads to the unloading effect of the upper soil,which is the internal cause of the bank slope deformation.