青藏高原构造变形圈-岩体松动圈-地表冻融圈-工程扰动圈互馈灾害效应

Interaction Disaster Effects of the Tectonic Deformation Sphere,Rock Mass Loosening Sphere,Surface Freeze-Thaw Sphere and Engineering Disturbance Sphere on the Tibetan Plateau

青藏高原板块强烈碰撞和持续变形的本质是地球圈层作用,地壳浅表关键带圈层作用研究是探索持续构造变形与浅表响应、巨灾孕育机制的关键.在简要分析青藏高原圈层作用动力背景的基础上,从工程地质视角,将地壳浅表关键带划分为四类圈层:构造变形圈、岩体松动圈、地表冻融圈和工程扰动圈,并分析研究了圈层岩土体变形破坏形式、圈层岩体稳定状态与工程安全性、圈层灾害行为与机制.研究表明,四类圈层的互馈作用深刻影响着不同尺度地质体的稳定性和灾害动力学机制.即:板块构造动力作用形成构造变形圈,制约区域地质体稳定性,控制灾害的孕育;高原隆升动力形成岩体松动圈,制约工程地质体稳定性,控制灾害的形成;气候变化动力形成地表冻融圈,制约工程岩土体稳定性,控制灾害链的演化;人类工程营力形成工程扰动圈,制约工程结构体稳定性,控制工程灾变发生.下级圈层对上级圈层具有包容性,且自下而上存在递进演化规律,使得岩体结构更加复杂,工程地质问题及灾害效应更加显著.上述认识为重大工程建设的地质安全风险防范提供了新思路.

The essence of intense collision and continuous deformation of the Tibetan Plateau plate is the effect of the earth′s sphere.It is also the key to explore the relationship of continuous tectonic deformation and shallow response,and catastrophe-pregnant mechanism.Based on the analyses of the dynamic background of sphere action on the Tibetan Plateau,this paper,from the perspective of engineering geology,divides the key zone of shallow crust into four types of the sphere,including tectonic deformation sphere,rock mass loosening sphere,surface freeze-thaw sphere,and engineering disturbance sphere.Meanwhile,this paper studies the deformation and failure law of rock-soil mass,the stability state and engineering safety of the rock-soil mass,as well as the behavior and mechanism of disaster in various spheres.This study shows that the mutual feedback of the four types of sphere has a profound impact on the geological body stability and disaster dynamic mechanism at different scales;that is,plate tectonic dynamic forms the tectonic deformation sphere,restricting the stability of regional geological body,and controlling the disaster-pregnant process;uplift dynamic of the plateau forms the rock mass loosening sphere,restricting the stability of engineering geological body,and controlling the formation of disasters;climatic change dynamic forms the surface freeze-thaw sphere,restricting the stability of engineering rock-soil mass,and controlling the evolution of disaster chains;human engineering force forms the engineering disturbance sphere,restricting the stability of engineering structures,and controlling the occurrence of engineering disasters.The lower sphere is inclusive of the upper sphere,and there is a progressive evolution law from bottom to top,which makes the rock-soil mass structure more complex,and the engineering geological problems and disaster effects more significant.This study provides a novel research idea for the geological safety risk prevention of major engineering construction.