基底伸展型地裂缝破裂扩展的物理模拟试验研究

Physical Simulation Experiment Study on Ground-fissure Expansion Mechanism of Basement Extension

基底伸展变化会引起上覆土层破裂,并导致地表建筑物、地下管线和隧道等结构物的变形与破坏。为探究基底伸展型地裂缝的发育过程及机制,通过物理模拟试验,揭示基底拉伸情况引起上覆土体形变和位移的变化规律,分析裂缝的剖面结构特征和发育破裂过程。结果表明,在基底张应力环境下,断层上覆土体会被"拉裂"而释放应力。随着水平拉伸活动的持续,上覆土体首先发生沉降和减薄,尤其是塑性较强的土体反应更明显,并在持续应力作用下,裂缝自下而上延伸扩展,直至贯穿地表。此外,越靠近地裂缝,土体的沉降量和减薄量越大,密度越小。

Changes in the basement tends to cause the overburden to rupture and deformation and damage to structures such as surface structures,underground pipelines,and tunnels.In order to explore the development process and mechanism of basement extensional ground fissures,this paper reveals the variation law of deformation and displacement of overlying soil caused by basement extension through physical simulation experiments,and analyses the section structure characteristics of fissures and the development and fracture process.The results show that under the tensile stress of the substrate,the overlying soil on the fault will be"pushed"to release stress.With the continuation of horizontal tension,the settlement and thinning of overlying soils occur first,and especially,the response of soils with strong plasticity is more obvious.Under the action of continuous stress,cracks extend from bottom to top until they penetrate the surface.In addition,the closer to the ground fissure,the larger the amount of sedimentation and thinning of the soil is,and the smaller the density becomes.