牵引式滑坡降雨预警判据的模型试验研究

Model Test on Rainfall Warning Criteria of Retrogressive Landslide

以河南省灵宝市麦尖窝滑坡作为试验对象,进行室内人工降雨模型试验,研究降雨作用下牵引式滑坡的变形破坏规律,并提出适用于研究区的降雨预警判据。采用含水率传感器、坡面示踪点和数码相机等仪器设备对关键部位含水率、坡面变形和裂缝发育情况进行监测、记录。试验表明:在强降雨作用下,边坡表现为自下而上的渐进式牵引变形破坏。通过分析模型各关键部位的变形破坏特征和含水率监测数据,确定牵引式滑坡变形破坏过程中的关键时间节点,并将整个过程划分为变形启动、变形加速和整体破坏3个阶段。基于以上变形破坏模式,提出以滑坡坡脚、坡肩表面出现贯通裂缝时的持续累计雨量E1(75 mm)、E2(180 mm)分别作为麦尖窝滑坡的橙色、红色降雨预警判据。

Indoor artificial rainfall simulation test was conducted to investigate the mechanism of retrogressive landslide,and the criteria of rainfall warning for the study were proposed. The Maijianwo landslide in Lingbao City of Henan Province was taken as a case study. In the model test,moisture sensors,tracking points and digital cameras were adopted to record variations in the moisture of crucial parts,the surface deformation and crack propagation.Research results showed that the rainstorm led to destruction from the bottom of slope to the top gradually as a retrogressive mode. The slope failure process was divided into three stages as deformation activation,deformation acceleration and integral destruction in accordance with the critical time points by analyzing the deformation characteristics and moisture monitoring data of crucial parts. According to the above failure mode,the cumulative rainfalls E1( 75mm) and E2( 180mm) were respectively set as the orange and red warning criteria for the Maijianwo landslide when there were penetrating cracks on the slope toe and shoulder.