陇西黄土构造节理几何特征分析  

Geometrical features of tectonic joints in loess of central Gansu and southern Ningxia

作　　者：康尘云 王少凯 贺鸣 KANG Chenyun;WANG Shaokai;HE Ming(School of Geology Engineering and Surveying,Chang’an University,Xi’an,Shaanxi 710054,China)

机构地区：[1]长安大学地质工程与测绘学院

出　　处：《中国地质灾害与防治学报》2019年第5期131-138,共8页The Chinese Journal of Geological Hazard and Control

基　　金：国家自然科学基金项目(41790441;41807234);长安大学中央高校基本科研业务费专项资金资助(300102269203)

摘　　要：节理影响岩土体的力学和渗流特性,是坡体失稳的几何和力学边界,准确分析陇西黄土构造节理发育特征,是理解该地区频发坡体灾害的关键性步骤。通过现场调查、结合数理统计、概率分析等方法,对该地区的节理几何特征进行系统研究。结果表明:(1)陇西地区发育走向为NWW、NNW和NE的优势节理,受区域走滑断裂和逆倾滑断裂控制;(2)节理倾角多在60°~80°,倾向和倾角均服从正态分布;(3)节理的平均间距服从正态分布,从西南向东北整体上呈增加趋势,延续性低,中等开裂;(4)节理连通率较小,92.5%的节理连通率小于0.4,不易发生贯通式破坏。研究结果可为掌握节理发育规律,恢复新构造应力场,乃至区域稳定性评价提供基础数据。Joints affect the mechanical and seepage characteristics of rock-soil mass,which is consider as the geometric and mechanical boundary of slope in stability.Accurate analysis of the development features of loess tectonic joints in Longxi is a key step to understand the frequent slope disasters in this area.Based on field investigation,mathematical statistics and probability analysis,the geometry of joints in this area are systematically studied.The results show that:(1)Longxi region has dominant joint group with trend NWW,NNW and NE,which are controlled by regional strike-slip and reverse tilting faults;(2)the inclination angles of joints are mostly between 60°and 80°,and the inclination and inclination angles obey normal distribution;(3)the average spacing of joints obeys normal distribution,and increases from southwest to northeast with low continuity and moderate cracking;(4)joint connectivity rate is small.92.5%joints have a connectivity rate of less than 0.4,which is difficult to occur through failure.The research results can provide basic data for researches of mastering the developmental law of tectonic joints,recovering the Neotectonic tectonic stress fields,as well as conducting regional stability assessment.

关 键 词：陇西黄土 构造节理 几何特征 优势节理组 连通率 

分 类 号：P642.131[天文地球—工程地质学]