微型碎石管注桩治理深部软岩巷道底鼓新方法

A new method for controlling of floor heave of deep tunnels in soft rocks by mini-tube grouting piles of crushed stones

针对造成巷道底鼓的物理和力学两种重要机制,研究并提出微型碎石管注桩治理深部软岩巷道底鼓的新方法。在物理机制方面,微型碎石桩具有渗透性极好的特点,在巷道施工和使用期间可汲取岩体中的渗水并透过碎石桩中的插管排出,从而降低软岩层因遇水膨胀导致的变形;在力学机制方面,微型碎石桩一方面通过钻孔置换出少部分底板软岩,从体量上减少变形岩体,另一方面能利用碎石桩体的侧向可压缩性耗散岩体水平变形,底板岩层中的水平地应力得以释放,极大减缓了促使底鼓变形的力学作用;通过微型碎石桩中的插管注浆加固底板岩体,提高了底板复合地基整体承载力。通过数值分析,阐明该方法在治理软岩巷道底鼓机制上的有效性。

Focusing on two important mechanisms of physics and mechanics that give rise to the floor heave of tun- nels, a new method of controlling the floor heave of deep tunnels in soft rocks was proposed by means of mini-tube grouting piles of crushed stones. In physical aspect, the crushed stone pile to absorb the water in rockmass and method utilizes the characteristics of good permeability of drainage out through the tubes in the pile during the con- struction and application of the tunnels, resulting in the decrease in expansion deformation of soft rock due to water saturation. In mechanical aspect, partial volume in floor stratum has been replaced, on one hand, by the installed mini piles which reduce the volume of the deforming rock body, and on the other hand, amount of horizontal de- formation are dissipated through the lateral compressive deformation of the crushed stone pile, and the horizontal stress is released. As a result, the mechanical affect that induces the heave deformation in floor stratum is consider- ably reduced. By means of grouting the crushed stones through the tube inserted in the pile, the floor stratum is re- inforced and the supporting capacity of the composed foundation of floor is ready to increase. Numerical simulation indicated the potential efficiency of the method.