滇中祥云盆地构造应力场孕灾机制及其应对措施研究

Study on the disaster mechanism and countermeasures of tectonic stress field in Xiangyun Basin of central Yunnan

亚欧板块和印度板块相互挤压碰撞导致青藏高原强烈隆升,地壳物质向云南滇西北及滇中西部地区挤入,地质构造活动剧烈,地质灾害频发。为探讨构造应力场特征对地质灾害发生的影响,利用区域构造解析法、节理分析法、共轭剪节理法和水系折线图法对研究区构造应力场进行反演,探究各类地质构造对地质灾害的控制作用,并针对构造诱发的地质灾害,提出相应的应对措施。研究结果表明,祥云盆地周缘发育北东、北西、近东西向断裂和节理构造,通过断层及节理的交切关系以及水系折线图法判断,研究区至少经历3次构造应力场作用,最大主应力σ1先后从北东向、北西向、近东西向转换。断裂构造通过控制水系演化间接诱发地质灾害,区内三岔河、苴力河等河流多沿断裂带发育,滑坡、崩塌等地质灾害多沿河流两岸边坡分布;地质构造多期次活动增强岩土体断裂网络系统的密集程度,致使岩土体透水能力增强,稳定性变差,导致滑坡、崩塌和泥石流等地质灾害发育。对于构造诱发的地质灾害防治,工程治理效果较差,文中提出优化建设区选址,搬迁避让和群测群防的应对措施。

The mutual extrusion and collision between the Asia-Europe plate and the India plate led to the strong uplift of the Qinghai-Xizang Plateau,the squeezing of crustal material into the northwest and central and western parts of Yunnan,the intense geological tectonic activity and frequent geological disasters.In order to explore the influence of tectonic stress field characteristics on geological disasters,this paper uses regional structural analysis method,joint analysis method,conjugate shear joint method and water system line graph method to invert the tectonic stress field in the study area,to explore the control effect of various geological structures on geological disasters,and to propose corresponding countermeasures for tectonically induced geological disasters.The results show that the north-east,north-west and near-east-west faults and joint structures are developed around the Xiangyun Basin,and the study area has experienced at least three tectonic stress fields through the intersection of faults and joints and the water system line diagram method,and the maximum principal stressσ1 has successively transformed from the north-east to the north-west to the near-east-west.The fault structure indirectly induces geological disasters by controlling the evolution of the water system.In the area,rivers such as Sancha River and Juli River are mostly developed along the fault zone,and geological disasters such as landslides and collapses are mostly distributed along the slopes on both sides of the rivers.The multi-period activities of the geological structure enhance the density of the fracture network system of the rock and soil mass,resulting in the development of geological disasters.For the prevention and control of geological disasters induced by structure,the effect of engineering management is poor,and this paper puts forward the countermeasures of optimizing the site selection of construction area,relocation avoidance and group survey and group prevention.