岩体洞室地基洞室两帮失稳的宏观判据
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摘要
岩体洞室地基是由岩体、地下洞室、地面建筑共同组成的有机整体,是由地下工程与地表工程共同组成的复杂系统。岩体洞室地基系统的稳定应保证基底岩体和洞室围岩均处于稳定状态,其稳定性判据包括"地基稳定性判据"和"洞室围岩稳定性判据"两个方面。其中,"地基稳定性判据"又包括岩体地基极限承载力计算(不考虑地下洞室的影响)和地基沉降计算(考虑地下洞室的影响)两部分,前者侧重于对岩体地基强度失效破坏模式的判别,以基底荷载是否超过极限承载力为判别依据,后者侧重于对岩体地基变形失效破坏模式的判别,以建筑物的变形是否超过允许变形值为判别依据;而洞室围岩稳定性判据则主要以洞室围岩的应力、应变是否超过允许值为判别依据,可采用解析分析法、赤平投影图解分析法、数值模拟法和考虑地应力影响的宏观判据进行判别。其中,洞室两帮可考虑岩体结构特征及所处的地应力环境,根据洞室围岩的岩性及节理分布特征,分为均质洞室、力学性质相近的岩层组中洞室、被节理切割成块体的洞室、具有软弱夹层时洞室等4种情况,来建立围岩失稳破坏的宏观判据。
The foundation for the underground space is an integral part of a complicated system consisting of rock mass,underground rock cavern and building structures above the ground.The stability of the underground space foundation should evaluate stability of rock mass underneath the rock cavern as well as the stability of surrounding rock mass.The failure criteria should include the"failure criteria of rock foundation"and the"failure criteria of surrounding rock mass".For the failure criteria of rock foundation,it includes two portions:the bearing capacity of rock mass excluding the influence of rock cavern and the settlement of foundation including the impact of rock cavern.The first portion is focused on the strength failure mode for the maximum bearing capacity that the rock mass could carry.The second portion is concentrated to deformation failure mode for the tolerable settlement for buildings above the ground.For the failure criteria of surrounding rock mass are for the examination of the stress and strain at the rock mass.The analytical method,the stereographic projection graphical analysis method and the numerical simulation method can be used in the stability analysis.Among all locations,the stability criteria for the rock mass at the side walls of the cavern are established for four different categories based on the structural characteristics,the stress level of rock mass and the rock joints:Uniform rock cavern;rock carven with similar rock properties;rock cavern in jointed rock mass and rock cavern.
The foundation for the underground space is an integral part of a complicated system consisting of rock mass,underground rock cavern and building structures above the ground.The stability of the underground space foundation should evaluate stability of rock mass underneath the rock cavern as well as the stability of surrounding rock mass.The failure criteria should include the"failure criteria of rock foundation"and the"failure criteria of surrounding rock mass".For the failure criteria of rock foundation,it includes two portions:the bearing capacity of rock mass excluding the influence of rock cavern and the settlement of foundation including the impact of rock cavern.The first portion is focused on the strength failure mode for the maximum bearing capacity that the rock mass could carry.The second portion is concentrated to deformation failure mode for the tolerable settlement for buildings above the ground.For the failure criteria of surrounding rock mass are for the examination of the stress and strain at the rock mass.The analytical method,the stereographic projection graphical analysis method and the numerical simulation method can be used in the stability analysis.Among all locations,the stability criteria for the rock mass at the side walls of the cavern are established for four different categories based on the structural characteristics,the stress level of rock mass and the rock joints:Uniform rock cavern;rock carven with similar rock properties;rock cavern in jointed rock mass and rock cavern.
引文
[1]谭云亮,刘传孝.巷道围岩稳定性预测与控制[M].徐州:中国矿业大学出版社,1999.
[2][波]A.吉迪宾斯基著.刘大泉,于振海译.采掘工程与矿井地质技术[M].北京:煤炭工业出版社,l989.
[3]耿大新,杨林德.层状岩体的力学特性及数值模拟分析[J].地下空间,2003,23(4):380-383.
[2][波]A.吉迪宾斯基著.刘大泉,于振海译.采掘工程与矿井地质技术[M].北京:煤炭工业出版社,l989.
[3]耿大新,杨林德.层状岩体的力学特性及数值模拟分析[J].地下空间,2003,23(4):380-383.