大断面硐室底鼓分步控制研究

Research on large section cave floor heave steps control

以曲江高坑暗皮带斜井机头硐室为工程背景,采用理论分析、数值计算、现场试验等手段,研究暗皮带斜井机头硐室的底鼓特征与机理,分析机头硐室底板应力分布情况。认为硐室底鼓及不对称变形的主要原因是频繁扰动影响、应力分布不均衡及围岩性质差等。根据底鼓分步控制原理,提出"第一步钻孔卸压,第二步锚索+槽钢+喷浆"的分步控制方式,并在该硐室实施。运用数值模拟比较分析新方案支护前后硐室塑形区和应力变化,工程实践表明该支护方案对控制机头两端相对位移和底鼓的效果良好。

Taking Qujiang Gao Keng subinclined belt shaft head chamber as the engineering background, it＇ s floor heave characteristics and mechanism and it＇ s floor stress distribution were analyzed by theoretical analysis, numerical simulation, field test method. The main reason of floor heave and asymmetric deformation was frequent disturbed, unbalanced stress distribution and rock properties etc. To control the stability of surrounding rock of the chamber, the key measures is to control the uniform stress distribution, followed by controlling the shallow rock stress concentration degree, and fi- nally improving the roadway surrounding rock. The surrounding rock deformation can be controlled. According to the principle of floor heave steps control,＂ the first step is to borehole pressure relief, the second step is to cable ＋ channel ＋ spray＂ is proposed and is put into effect in that tunnel. The new supporting scheme chamber plastic zone and stress change with original supporting scheme were compared by utilizing numerical simulation. Engineering practice shows that the new supporting scheme effect is good for controlling the relative displacement of head ends and the floor heave, the key measures is to control the uniform stress distribution