隧道全方位高压喷射注浆拱棚超前支护新技术

NEW TECHNIQUE OF ROTARY HORIZONTAL JET GROUTING FOR ARCHED TUNNEL PRE-SUPPORT

基于对目前国内外隧道水平旋喷技术差距的分析,指出国内现有水平旋喷技术存在的成桩质量差、加固体周边岩土体变形大以及废浆液无序排放等问题。为突破隧道水平旋喷超前支护施工的关键技术,研制出大型液压双摇臂式全方位高压喷射注浆钻机,以及具有自主知识产权的配套孔口止浆器装置,并探索出一整套带孔口止浆器的隧道全方位高压喷射注浆拱棚超前支护新技术。通过现场足尺试验研究实例,详细介绍了这项新技术的全套施工工艺、施工参数及其配套机具装备,并全面展示了足尺试验旋喷拱棚的几何形态、桩–桩咬合尺寸、旋喷拱棚厚度、拱棚水泥土加固体的28 d抗压强度以及6 m长隧道开挖效果的实测资料。足尺试验成果表明,这项新技术安全可靠、工艺先进、经济环保,基本上解决了国内现有水平旋喷技术所面对的主要难题,为我国隧道超前支护工程领域提供了全新的技术手段以及配套的工法设备。

Based on the analysis of the technical difference of horizontal jet grouting for tunnel arch between China and the developed countries, it is easy to find some construction problems, such as the quality control, serious deformation and waste grout discharge during tunnel horizontal jet grouting in China. In order to master the key technique of tunnel horizontal jet grouting, a large advanced drilling rig and a patented seal equipment have been developed; furthermore, a new construction method of horizontal jet grouting with invented seal equipment for the tunnel pre-support has been proposed. By a full-scale field testing executed by the abovementioned construction method, the useful technique, its matching drilling rig and its equipments, and the relative construction parameters are introduced. Additionally, all test results which include the geometric form of the horizontal jet grouting arch of tunnel, the connection thickness of pile to pile, the minimum thickness of horizontal jet grouting arch, the strength of piles in 28 days, and the 6 m long excavation of tunnel under pre- support system as well, are well demonstrated. The results of full-scale testing show that the new technique to be safe and reliable, having the advantages of reasonable construction sequence, cost effective and environmental protection. It is believed that this new construction technique has successfully solved the existing problems of horizontal jet grouting in China, and it will have a good prospect for future sub-horizontal treatment ahead of the tunnel excavation face.