文章摘要

文章信息/Info

Title:: Mechanism of Large-scale Deformation in Mianning Cross-fault Short-level Based on Finite Element Method

作者:: 岳冲¹; 2; 赵静¹; 牛安福¹; 吉平¹; 李晓帆¹; 苏琴³; 杨凡⁴; (1.中国地震台网中心,北京 100045; 2.中国地震局地质研究所地震动力学国家重点实验室北京 100029; 3.四川省地震局测绘工程院,四川雅安 625000; 4.河北省地震局,河北石家庄 050021)

Author(s):: YUE Chong¹; 2; ZHAO Jing¹; NIU Anfu¹; JI Ping¹; LI Xiaofan¹; SU Qin³; YANG Fan⁴; (1.China Earthquake Networks Center,Beijing 100045,China)(2.Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China)(3.Survey Engineering Institute,Sichuan Earthquake Agency,Ya'an 625000,Sichuan,China)(4.Hebei Earthquake Agency,Shijiazhuang 050021,Hebei,China)

Keywords:: Mianning cross-fault short-level; finite element method; Mohr-Coulomb; fluid-solid coupling model

摘要:: 分析计算安宁河断裂带上冕宁跨断层水准场地原始观测数据及年均速率结果,结合1-1C测段加密观测数据的差异性特征,重点对滑坡、抽水2个主要影响因素,利用有限元方法构建该场地三维Mohr-Coulomb弹塑性滑坡体模型及二维抽水影响的单向流固耦合模型,模拟获得2种主要因素的影响模式。结果显示:冕宁水准1-1C测线中距离1C点约300 m范围为古滑坡体所处边坡的坡脚区域,古滑坡体对坡脚区域长期的累积作用使得该区域存在隆升变形特征,进而使1-1C测段在抽水造成的大幅下降过程中出现沉降量逐渐减小后再次增大的特征; 地下水抽取造成沿水井形成了较为明显的抽水漏斗沉降变形特征,在含水系统平衡被打破后,1号点所处土体边坡更易受到抽水带来的沉降变形影响,出现与井口处相当甚至比井口附近更大的沉降变形。

Abstract:: Firstly,we analyzed original observation data and calculated the average annual rate of the Mianning fault-crossing short-level site on the Anninghe fault zone.Then combined different characteristics of encrypted observation data in the 1-1C segment,we mainly focused on the two main influencing factors of landslide and pumping.Finally we constructed the three-dimensional Mohr-Coulomb elastoplastic landslide models and the two-dimensional fluid-solid coupling model of the pumping by the finite element method,and obtained the influence modes of two main factors by simulation.The result showed that:The range of about 300 m from the 1C point in the Mianning 1-1C segment is the slope toe area where an ancient landslide body is located.The long-term cumulative effect of the ancient landslide body on the slope toe area makes this place uplift,which caused the 1-1C segment to gradually decrease and then increase again during the large settlement induced by pumping.The groundwater pumping caused obvious deformation characteristics of the pumping funnel along the well.However,due to the influence of the free drainage surface and loose sediment layer,the point 1 on the slope is more susceptible to the settlement deformation caused by pumping after the balance of the water-bearing system was broken,which made the settlement deformation in this area comparable to or even greater than that near the well.