新增建筑荷载与下伏煤矿采空区相互作用规律研究

Study on the interaction law between new building load and goaf in coal mine

采空区在新增建(构)筑物作用下有可能发生“活化”变形,危及建筑物安全。为研究采空区建筑物地基的受力和变形特性,以晋城某采空区为例,采用FLAC 3D数值软件对采空区建筑物地基受新增荷载后的应力分布及沉降规律进行了研究。结果表明:开采前岩体应力基本随岩层深度线性变化,开采后岩体应力发生了复杂的应力重分布;在采空区中部及内外边缘处,地基沉降倾斜值、沉降差及曲率呈现不同变化特征;岩土层的附加应力与自重应力的比值越小,建筑荷载的影响深度越大;煤层采深采厚比越大,采空区对地表的影响作用越小;在采空区地基处理中,注浆充填是一种行之有效的治理手段。采空区的存在对新增建筑地基稳定性造成了不同程度的影响,在新增建筑荷载影响深度触及到采空区垮落裂缝带高度时,需对采空区进行加固处理,以确保建筑物的安全。

In the goaf,there may be“activation”deformation under the action of newly built structures,which endangers the safety of buildings.In order to study the bearing and deformation characteristics of the foundation of the goaf,this paper combines a goaf in Jincheng and adopts the FLAC 3D numerical software to study the stress distribution and settlement law of the foundation of the goaf under new load.The results show that the stress of the rock mass changes linearly with the depth of the rock before mining,and the complex stress redistribution occurs after the mining.The slope of the foundation settlement,the settlement difference and the curvature show different changes at the middle and inner edges of the goaf.The smaller the ratio of the additional stress to the self-weight stress in the geotechnical layer,the greater the depth of influence of the building load.The greater the mining-thickness ratio of the coal seam,the smaller the effect of the goaf on the surface.The treatment of the ground in the goaf grout filling is an effective means of governance.The force and deformation characteristics of the goaf indicate that the existence of the goaf has affected the stability of the new building foundation to varying degrees.When the depth of the new building load affects the height of the fallen crack zone in the goaf,the goaf is reinforced to ensure the safety of the building.