地铁隧道高压喷射注浆技术试验研究

Experimental Study of Jet Grouting with High Pressure in Subway Tunnel

MJS工法是在旋喷机具中加入强制排浆管,通过强制排浆来保持地内压力,控制其对加固范围外土体的影响。但其外管直径较大,开孔会破坏管片主筋,无法直接应用到盾构地铁隧道内。因此,利用其强制排浆的特点,开发管径较小、对周围土体扰动小、可以在地铁盾构隧道内施工的旋喷设备。为验证改造后设备的效果,利用改造后的设备对特定的土层进行旋喷加固试验,在试验过程中使用单点位移计监测上覆土层隆沉情况,使用测斜孔监测试验过程中对周围土体的扰动情况,并采用静力触探来探测喷浆加固效果和加固范围。通过对喷浆加固效果和加固范围以及引起上覆及周围土体变形量的分析,为隧道内不均匀沉降段下卧土层喷浆加固提供借鉴和参考。

MJS is a skill in which the compulsory pulp discharging tube is added to rotary jet grouting machine. The surrounding soil disturbance is controlled by pumping out the soil actively to keep the soil pressure balanced. MJS cannot be used to the shield tunnel directly because of the grouting machine where the diameter of its outer tube is too large which will lead to the damage of the main steel in shield segment. By using of compulsory pulp discharging tube,new equipment is developed which can be used in tunnel directly owing to smaller diameter and lower disturbance. A selected soil is reinforced by jet grouting with the new developed equipment to verify its effect,the amount of soil heave is measured with single-point displacement meter,the degree of soil disturbance is measured with inclinometer tube,and the reinforcing effect and range are measured with cone penetration test. The data of jet grouting reinforcement effect scope and soil deformation on all sides are analyzed to provide experiences and references for the grout reinforcement of soil at uneven settlement section in shield tunnel.