矿柱下软弱夹层的极限承载力分析  

Analysis of Ultimate Bearing Capacity of Soft Interlayer under Pillar

作　　者：殷勇[1,2] 乔来军[3] 周国庆[1] 

机构地区：[1]深部岩土力学与地下工程国家重点实验室,江苏徐州221008 [2]盐城工学院土木工程学院,江苏盐城224051 [3]中煤国际工程集团北京华宇工程有限公司,河南平顶山467002

出　　处：《金属矿山》2015年第5期55-60,共6页Metal Mine

基　　金：国家重点基础研究发展计划(973计划)项目(编号:2012CB026103)

摘　　要：软弱夹层是一种广泛存在的地质构造,地下采矿工程中软弱夹层的存在往往给矿柱的设计及稳定性分析带来不利。针对软弱夹层的极限承载力,采用Prandtl塑性挤出破坏模式和极限分析上限法,同时考虑夹层面不同位置的剪应力条件,求得了平面应变条件及空间轴对称条件下软弱夹层极限压力的计算式。对计算数据的分析表明,软弱夹层的极限压力与夹层的宽高比及夹层面的摩擦系数之间具有一定的规律。总体而言,软弱夹层的极限压力随夹层的宽高比及夹层面摩擦系数的增加而增大,同时夹层面的摩擦条件对极限压力的影响也随宽高比的增加而更加显著,但摩擦系数增加至一定程度时其对各种宽高比尺度下极限压力的影响逐步减弱直至消失。此外,与夹层面采用单一摩擦条件的其他方法相比,夹层宽高比较小时所得到的解答与其他方法解答相差不大,夹层宽高比较大时解答结果高于其他方法,但在摩擦系数或粗糙程度极高的情况下几种方法的解答近似相等。推导得出的极限承载力计算式可以为下伏软弱夹层的矿柱设计及稳定性分析提供参考。Soft interlayer in rock and soil mass is a widespread geological structure. In underground mining engineering,the existence of soft interlayer will bring disadvantages to the design and stability analysis of pillar. In view of the ultimate bear-ing capacity of soft interlayer, based on Prandtl＇s plastic extrusion failure mode and upper bound limit analysis method, formu-lae of ultimate pressure of soft interlayer are deduced under plane strain condition and space axisymmetric condition,where dif-ferent shearing stress conditions of various locations on the surface of soft layer are also taken into account. Analysis of calculat-ed data shows that,the ultimate pressure of soft interlayer has a relationship with width-height ratio of soft interlayer and fric-tion factor on its surface. In general, the ultimate pressure of soft interlayer is enhanced both with the increase of its aspect ratioand friction factor on its surface, and the effectiveness of friction conditions on its surface is even more significant with the in-crease of aspect ratios. However, as the friction factor increased to a certain degree,its effect on ultimate pressure in various as-pect ratio scales will gradually diminish until it vanishes. Besides, comparison with other methods adopted single friction condi-tion on the surface of soft interlayer demonstrates that, the solution in the paper is almost the same with others with the smalleraspect ratio and is higher than others with a larger aspect ratio. Furthermore, as the friction factor and roughness on interlayersurface is extremely large, solutions of other methods including this text are identical approximately. The formula of ultimatebearing capacity could provide a reference to the design and stabilization analysis of a soft interlayer underlying pillars.

关 键 词：矿柱地基 软弱夹层 塑性挤出破坏 层面摩擦条件 极限承载力 

分 类 号：TD311[矿业工程—矿井建设]