泾阳-渭南活动断裂带场地形变与地层应力特征数值分析  

Numerical analysis of site deformation and formation stress characteristics of Jingyang-Weinan active fault zone

作　　者：陈绰裕 黄强兵[1,2] 解庆禹 李伦 CHEN Chuoyu;HUANG Qiangbing;XIE Qingyu;LI Lun(School of Geological Engineering and Surveying,Chang’an University,Xi’an,Shaanxi 710054,China;Key Laboratory of Western China’s Mineral Resources and Geological Engineering,Ministry of Education,Xi’an,Shaanxi 710054,China)

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054 [2]西部矿产资源与地质工程教育部重点实验室,陕西西安710054

出　　处：《水文地质工程地质》2024年第5期136-149,共14页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金项目(41772274,41372328);陕西省科技创新团队项目(2021TD-50,2021TD-51)。

摘　　要：西安地铁十号线穿越的泾阳—渭南断裂,该断裂为全新世活动断裂,黏滑发震与同震位错对地铁线路构成潜在安全威胁。为揭示泾阳—渭南断裂带黏滑发震和同震位错作用引起的场地形变与地层应力特征,以西安地铁十号线穿越泾阳—渭南断裂带为工程背景,建立断裂带场地同震位错与黏滑发震地质力学模型,考虑不同位错量及发震强度,开展断裂带场地形变及应力场特征的数值模拟分析。结果表明:同震位错下场地在断裂带附近上、下盘分别出现应力降低区和增强区,场地呈反“S”形差异沉降破坏,差异位移在断裂带处达到峰值且塑性区集中,上盘变形范围与塑性区分别为下盘的1.67倍和2.50倍;黏滑发震作用下场地在断裂带附近位移量及差异形变均达到峰值,大震时场地位移影响范围约为中震的6.50倍,且具有典型的上盘放大效应,远离断裂带时位移呈线性递减;大震时地表峰值加速度放大系数受影响范围为中震时1.14倍,场地呈“V”形剪切破坏,上盘塑性区范围约为中震时1.40倍,而下盘则为1.00倍。研究结果可为西安地铁线路穿越泾阳—渭南断裂带场地的抗震设防提供科学依据与参考借鉴。The Jingyang–Weinan Fault that Xi’an Metro Line 10 crosses is a Holocene active fault,and its future stick-slip earthquakes and coseismic dislocations pose a potential threat to the metro line.To reveal the deformation and stratum stress characteristics of the site caused by the stick-slip seismic and coseismic dislocations of the Jingyang–Weinan Fault zone,based on the Jingyang–Weinan fault zone crossed by Xi’an Metro Line 10,the geomechanical model of the fault zone site coseismic dislocations and stick-slip seismic was established,and the numerical simulation analysis of the stratum deformation and stress field characteristics of fault zone site was carried out considering different dislocation amounts and seismic intensity.The results show that under the coseismic dislocation,the stress reduction and strengthening zones appear in the hanging wall and footwall near the fault zone,and the site presents an inverse“S”shaped differential settlement failure.The differential displacement peaks at the fault zone,and the plastic zone is concentrated here.The deformation range and plastic zone of the hanging wall are 1.67 times and 2.50 times more than that of the footwall,respectively.The displacement and differential deformation of the site near the fault zone reach the peak value under the stick-slip earthquake.The influence range of the site displacement during the large earthquake is approximately 6.50 times more than that during the medium earthquake.It has a typical magnification effect on the hanging wall,and the displacement decreases linearly far away from the fault zone.The amplification factor of peak surface acceleration(PGA)in the large earthquake is 1.14 times more than that in the medium earthquake.The site shows“V”shear failure;the plastic zones of hanging wall and footwall in the large earthquake is about 1.40 times and 1.00 times larger than that in the medium earthquake,respectively.This study can provide a scientific basis for the seismic fortification of Xi’an Metro Line lines

关 键 词：泾阳—渭南活动断裂 同震位错作用 黏滑发震 场地形变 地层应力 数值模拟 

分 类 号：P642.4[天文地球—工程地质学]