大跨度破碎岩体顶板预应力锚固支护机理及效果研究  

Mechanism and effect analysis of prestressed anchoring support mechanism of long-span crushed rock mass roof

作　　者：龙赣 王俊[1] 乔登攀[1] 李子彬 施仁智 张希 LONG Gan;WANG Jun;QIAO Dengpan;LI Zibin;SHI Renzhi;ZHANG Xi(Faculty of Land Resources Engineering,Kunming University of Science and Technology,Kunming 650093,China;Baoshan Jinchanghe Mining Corporation Limited,Baoshan Yunnan 678000,China;Liangshan Mining Corporation Limited,Liangshan Sichuan 615141,China)

机构地区：[1]昆明理工大学国土资源工程学院,昆明650093 [2]保山金厂河矿业有限公司,云南保山678000 [3]凉山矿业股份有限公司,四川凉山615141

出　　处：《有色金属（矿山部分）》2024年第3期101-111,124,共12页NONFERROUS METALS(Mining Section)

基　　金：云南省基础研究专项-青年项目(202101AU070022);昆明理工大学人培基金(KKZ3202021040)。

摘　　要：大跨度破碎岩体顶板采用预应力锚固支护,能最大程度地维持顶板围岩稳定,因此研究预应力锚固对大跨度破碎岩体顶板的支护机理及支护效果,对于保障破碎岩体下大跨度地下工程、露天大断面隧道工程的长期稳定性具有重要意义。对锚固后锚固体强度变化进行力学解析,剖析大跨度破碎岩体顶板预应力锚固支护机理,以云南金厂河多金属矿Ⅳ级破碎岩体大跨度顶板支护难题为工程背景,针对其支护方式建立数值模型进行分析,对FLAC3D软件中结构单元Cable的布置,设计新的三段式布置法,将预应力锚杆(索)在FLAC3D软件层面分为预紧段、自由段、锚固段分别赋予指定参数进行数值计算,建立3组不同支护方式的数值模拟方案对预应力锚固支护效果进行验证。结果表明:预应力锚固后,支护区域顶板受拉应力基本小于破碎岩体顶板抗拉强度,塑性区体积对比普通无预应力支护方案,下降比率达到61.95%,顶板Z方向垂直沉降量降低比率高达83.90%,预应力锚固范围内围岩得到了有效控制。The roof of a large-span broken rock mass is supported by prestressed anchorage,which can maintain the stability of the roadway roof to the greatest extent.Therefore,it is of great significance to study the supporting mechanism and supporting effect of prestressed anchorage on the roof of large-span broken rock mass for ensuring the long-term stability of large-span underground engineering and open-pit large-section tunnel engineering under broken rock mass.The strength change of anchorage body after anchorage is analyzed and the pre-stressed anchorage support mechanism of the roof of large-span broken rock mass is analyzed.Taking the support problem of large-span roadway in grade IV broken rock mass of Jinchanghe Polymetallic Mine as the engineering background,a numerical model is established for its support mode.The layout of structural unit Cable in FLAC 3D software,the key part of numerical model establishment,is analyzed.A new three-stage layout method is designed.The bolt and anchor cable are divided into pre-tightening section,free section,and anchorage section at FLAC 3D software level,and their specified parameters are given for numerical calculation.Three groups of numerical simulation schemes with different support methods are established to prove the effect of prestressed anchorage support.The results show that the tensile stress of the roof in the support area is less than the tensile strength of the broken rock mass roof.Compared with the ordinary non-prestressed support design scheme,the plastic zone volume decreases by 61.95%,and the vertical settlement of the roof in the Z direction decreases by 83.90%.The surrounding rock in the prestressed anchorage range is effectively controlled,and the safety of the stope roof is guaranteed.

关 键 词：破碎岩体 大跨度顶板 预应力 支护机理 数值模拟 

分 类 号：TD353[矿业工程—矿井建设]