南水北调中线工程砂土地震液化和变形破坏动力数值分析——以漳河河漫滩段为例

发布时间：2018-12-14 03:10

【摘要】：砂土液化问题一直是土动力学与岩土地震工程研究领域的重要课题之一.基于南水北调中线一期工程总干渠漳河河漫滩段工程,通过现场和室内试验获取岩土体的动力学参数,利用岩土数值分析FLAC3D软件,砂土本构模型选为Finn模型,输入近场地邯郸台记录的实际地震波,对渠基砂土地震液化和渠道变形破坏特征进行了动力数值分析.结果表明,在地震作用下,超静孔隙水压力最大值位于渠堤底部砂土层中,但渠堤底部砂土层由于初始应力较大,其孔压比不高,不会发生液化;在渠道底部以及渠堤外侧坡面平台至坡脚局部区域土体虽然超孔隙水压力较小,但有效应力小,超孔压比反而大,砂土层发生了液化;在地震作用下变形主要发生在渠堤和浅层地基土里,具有对称性;渠堤边坡的变形破坏主要表现为在渠堤顶面发生震陷和拉裂破坏,在坡脚处发生水平侧向流动和挤压隆起变形.计算过程中,在渠堤及地基的不同位置设置监测点,得到了地震作用过程中不同位置处超孔隙水压力、有效应力和位移的动态变化规律.通过剪应变增量判断,在地震力作用下渠堤及地基中形成了贯通的剪切滑动面,易发生整体滑动破坏.研究成果对南水北调砂土液化特性的认识和防治有一定的意义.
[Abstract]:Sand liquefaction has always been one of the most important topics in the field of soil dynamics and geotechnical seismic engineering. The dynamic parameters of rock and soil mass were obtained by field and laboratory tests based on the first stage project of the main canal of Zhanghe River in the middle route of South-to-North Water transfer Project. The geotechnical numerical analysis software FLAC3D was used, and the sandy soil constitutive model was selected as Finn model. The actual seismic waves recorded by Handan station near the site were input and the characteristics of seismic liquefaction and channel deformation and failure of channel based sandy soil were analyzed by dynamic numerical method. The results show that the maximum pore water pressure is located in the sand layer at the bottom of the canal embankment under earthquake, but the liquefaction will not occur because of the large initial stress and the low pore pressure ratio at the bottom of the channel embankment. Although the excess pore water pressure is small at the bottom of the channel and the local area from the platform to the foot of the slope outside the canal embankment, the effective stress is small, the ratio of the excess pore pressure to the excess pore pressure is larger, and the sand layer is liquefied. The deformation occurred mainly in the canal embankment and shallow foundation soil under the action of earthquake, and it has symmetry. The deformation and failure of canal embankment slope are mainly caused by seismic subsidence and tensile cracking at the top of the canal embankment and horizontal lateral flow and extrusion deformation at the bottom of the slope. In the course of calculation, monitoring points are set up in different positions of canal embankment and foundation, and the dynamic variation law of excess pore water pressure, effective stress and displacement at different positions during earthquake action is obtained. By judging the increment of shear strain, a through shear sliding surface is formed in the canal embankment and foundation under the action of seismic force, which is prone to the whole sliding failure. The research results have certain significance for the understanding and prevention of liquefaction characteristics of sand soil in South-to-North Water transfer Project.
【作者单位】：华北水利水电大学资源与环境学院;河北省水利水电第二勘测设计研究院;
【基金】：国家自然科学基金青年基金资助项目(41102203) 水利部公益性行业科研专项经费项目(201301034) 河南省科技创新人才计划河南省基础与前沿技术研究项目(122300410146) 华北水利水电大学青年科技创新人才支持计划项目
【分类号】：TV68;TU435

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