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2009年10月3日,攀枝花机场260×104m3万方的高填方预加固边坡整体失稳,沿基覆界面下滑,并超覆于其下方的易家坪老滑坡之上,使易家坪老滑坡再次复活。这一填方边坡失稳事件最终导致机场停航两年。通过大型离心模型试验,再现了攀枝花机场预加固高填方边坡的滑动失稳过程,获得了边坡变形破裂的特征参量,阐明了边坡的滑动失稳机制。研究表明:天然工况下,边坡变形以坡顶沉降和沿基覆界面软弱层的蠕滑为主,坡体总体处于蠕滑变形状态;降雨和地下水工况下,坡体中后部拉张破裂和中前部挤压变形显著,具有塑性流动及推移式破坏特征,并最终产生溃滑失稳;预加固抗滑桩承受较大的边坡变形推力,且越靠近坡体后部的桩推力越大,最终从后向前逐排产生累进性剪断破坏,说明该填方边坡多排抗滑桩的平面布置和受力确定欠合理;降雨和地下水工况下,坡体的最大孔隙水压力是天然工况下的3.7倍,孔隙水压力对坡体失稳有重要作用;通过模型和原型的综合对比分析,该边坡的滑动失稳机制为推移式蠕滑-累进性折断-溃滑与超覆。
On October 3, 2009, the prefabricated slope of 260 × 104m3 Wanfang at Panzhihua Airport went down and fell along the interface of the foundation and overlying the old fault of the Yijiaping below it, Ping old landslide revived again. This filling slope instability event eventually led to the airport suspended for two years. The large-scale centrifugal model test reproduces the sliding instability of the prefabricated high-fill slope at Panzhihua Airport and obtains the characteristic parameters of the slope deformation and fracture, and expounds the slip-instability mechanism of the slope. The results show that under natural conditions, the deformation of the slope is dominated by the settlement of the top of the slope and the creep of the weak layer along the interface between the foundation and the foundation, and the slope body is in the state of creeping deformation. Under rainfall and groundwater conditions, Zhang fracture and mid-front extrusion deformation is significant, with plastic flow and pushover failure characteristics, and eventually slip and instability; pre-reinforced anti-slide pile to withstand greater deformation of the slope thrust, and the more close to the rear of the slope The greater the pile thrust is, the more the shear failure will occur from the rear to the front, which shows that the plane layout and stress determination of multi-row anti-slide piles are not reasonable. Under rainfall and groundwater conditions, the maximum of slope Pore water pressure is 3.7 times of that under natural conditions. Pore water pressure plays an important role in slope instability. Through the comprehensive comparison between the model and the prototype, the sliding instability mechanism of the slope is progressive creep-progressive fracture - Slip and overrun.