摘要
以典型的上行开采为工程背景,采用现场实测、物理模拟和数值计算相结合的综合研究方法,对上行开采上覆岩层应力场、裂隙场进行了研究,并分析侧压系数、断面形状、围岩强度等因素对围岩稳定性影响,揭示了上行开采采动应力分区特征及裂隙呈分域特性的时空演化规律,得到了基于采动巷道围岩稳定性的上行开采顶板岩层区划和巷道布置,将覆岩划分5个破坏区,裂隙分为4个区;提出了"等效开挖"和"低效加固区"的概念,给出顶板巷道应根据侧压系数λ的大小和主应力方向选择合理断面形状是圆形或椭圆以及底板4.0～6.0m必要的加固深度,形成了上行开采顶板巷道稳定性控制原理:选择应力降低的Ⅱ区和Ⅲ区布置巷道、确定采后165d为顶板巷道开挖时机、优化巷道断面和减小低效加固区、提高围岩强度和支护结构稳定性以及分区强化控制,成功指导工程实践.
Field measurements, physical simulations, and numerical modeling were used to de- termine the stress and fracture fields in overlying strata during ascending mining. The stability of the surrounding rock was studied and the lateral pressure coefficient, sectional shape, and rock strength were analyzed. Stress distribution and fracture evolution were determined as a function of time. The stability of rock surrounding a coal mine roadway is discussed. The roof strata are divided into regions; five damage zones in the overburden and four fractured regionsl The concepts of ＂equivalent excavation＂ and ＂inefficient reinforcement zone＂ are proposed. The lateral pressure coefficient and the orientation of the principal stress suggest a circle or an el- lipse would be a reasonable cross section for the roadway roof. Hence, increasing the depth of the floor by four to six meters is an effective action. Control principles for roof stability during ascending mining are proposed. Zones II and III are chosen for layout of the roadway. A period of 165 days after mining should be allowed before excavation. The cross section should be optimized and the inefficient reinforcement zone and stability of the support structure should should be decreased. Surrounding rock strength also be improved. These actions will successfully guide engineering practice toward control of zone strength.
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2012年第4期543-550,共8页
Journal of China University of Mining & Technology
基金
国家重点基础研究发展计划(973)项目(2011CB201200)
国家青年科学基金项目(50904064)
河南理工大学博士基金项目(648729)资助
关键词
煤层群
上行开采
采动应力场
采动裂隙场
顶板区划
顶板巷道
multiple seams
ascending mining
mining induced stress field
mining induced fracture field
roof regionalization
roof roadway
