攀枝花机场12#滑坡形成机理的离心模型试验研究

发布时间：2018-07-21 13:06

【摘要】：西南地区有多个在建或已建机场,由于山区众多,地形地质条件复杂,机场建设多具有多挖方、高填方、高地震烈度等特点。而高填方斜坡失稳也给各国人民生命财产及经济建设带来严重损失。因此,高填方斜坡失稳机理的研究对于工程建设具有重大意义。本文借助成都理工大学500gt大型土工离心机,以攀枝花机场12#滑坡为背景,模拟在降雨及地下水的情况下斜坡的变形破坏特征,旨在重现其破坏过程,通过高速摄像机及一系列测试元件,分析讨论其滑动破坏机理,主要研究成果如下:(1)设计并研发了一套新型离心模型降雨试验装置,包括雾化离心喷淋系统,加压加压系统,照明系统等,该装置能够与模型箱密闭,有效的解决了之前离心机降雨不均匀的问题;(2)以攀枝花机场填方体为原型按照模型比N=400来堆筑三维离心模型,并着重考虑了填筑体砂泥、泥岩的分布,并考虑三排抗滑桩,增加道面及地下水模拟装置,尽可能的对机场高填方真实情况进行模拟。在150g加速度的情况下来进行降雨模拟,以求真实还原高填方斜坡的变形破坏过程。共计使用测试元件土压力传感器、孔隙水压力传感器、应变片、位移传感器等60余个。(3)根据实验结果及监测元件显示,斜坡在初期以沉降蠕滑为主,最大沉降约4cm,相当于原型6m。并且在变形初期推测其行形成了细小的拉裂缝,降雨之后约2000s之后,位于坡肩以里的U1孔隙水压力传感器最先有反应。并且随降雨入渗孔压在不断增大,最大可达84.43kPa。(4)变形阶段经历两次大暴雨之后,坡体发生明显滑动破坏。在此阶段由于持续蠕动土压力一直减小,桩体所受压力一直增大,达66.22MPa。从桩身应变数据也可以看出,后排桩所受的内力远远比前排大,桩体面向滑动方向所受内力比背面大。(5)实验模型破坏起始于坡顶平台,坡肩部位变形最大,并且从平面上看左侧变形比右侧大。试验结果与12#滑坡变形破坏过程相似,从斜坡变形破裂特征,抗滑桩受力、孔压土压等多方面深化了滑坡滑动机制认识,验证了滑坡滑动机制是推移式蠕滑-溃滑与超覆。
[Abstract]:There are many airports under construction or have been built in southwest China. Due to the numerous mountainous areas and complicated terrain and geological conditions, the airport construction is characterized by many excavations, high fill and high seismic intensity. The instability of high-fill slope also brings serious loss to people's life, property and economic construction. Therefore, the study of instability mechanism of high fill slope is of great significance to engineering construction. In this paper, with the aid of 500gt geo-centrifuge of Chengdu University of Technology, taking the No. 12 landslide of Panzhihua Airport as the background, the deformation and failure characteristics of the slope under the condition of rainfall and groundwater are simulated in order to reproduce the failure process. Through high speed camera and a series of test elements, the mechanism of sliding failure is analyzed and discussed. The main research results are as follows: (1) A set of new centrifugal model rainfall test device is designed and developed, including atomization centrifugal spray system and pressure system. Lighting system, the device can be sealed with the model box, effectively solve the previous centrifuge rainfall uneven problem; (2) based on Panzhihua Airport fill body as the prototype according to the model to build a three-dimensional centrifuge model NC400, The distribution of sand-mud and mudstone is considered emphatically, and three rows of anti-slide piles are considered. The simulation device of pavement and groundwater is added to simulate the real situation of airport high fill as far as possible. The rainfall simulation is carried out at the acceleration of 150g in order to restore the deformation and failure process of the high fill slope. More than 60 earth pressure sensors, pore water pressure sensors, strain gauges and displacement sensors are used. (3) according to the experimental results and monitoring elements, the slope is mainly composed of subsidence creep at the initial stage, the maximum settlement is about 4 cm, equivalent to 6 m prototype. At the beginning of deformation, it is assumed that the line formed a fine tensile fracture, and after about 200s of rainfall, the U1 pore water pressure sensor located in the slope shoulder was the first to react. And with the increase of infiltration pore pressure, the maximum is 84.43 KPA. (4) after two torrential rains in the deformation stage, the slope body slides obviously. At this stage, the pressure on the pile has been increased to 66.22 MPa due to the continuous creep earth pressure has been reduced. It can also be seen from the strain data of the pile body that the internal force of the back row pile is much greater than that of the front row, and the internal force of the pile body facing the sliding direction is greater than the back side. (5) the damage of the experimental model starts from the slope top platform, and the deformation of the shoulder of the slope is the greatest. And from the plane, the deformation on the left side is larger than that on the right side. The experimental results are similar to the deformation and failure process of the No. 12 landslide. The landslide sliding mechanism is verified by deepening the understanding of landslide sliding mechanism from the aspects of slope deformation and fracture characteristics, anti-slide pile force, pore pressure and soil pressure, etc.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

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