漂卵石地层盾构掘进出渣量控制及超方判断技术

Slag Volume Control and Exceeding Excavation Judgment Technology for Shield Tunneling in Gravel-boulder Foundation

漂卵石地层地质复杂多变、级配不均,具有高富水、高强度、低粘聚力、自稳性差、漂石含量多、粒径大等特点;盾构掘进时渣土改良困难、刀盘扭矩和掘进速度波动大,造成掘进过程中出渣量难以控制;掘进出渣量超方会形成地层空洞,继而引发地面塌陷或造成周边建筑物、地下管线损坏等安全风险。本文通过系统分析成都地铁漂卵石地层盾构施工中影响出渣量的因素和控制措施及超方后地层空洞的形成机理,总结形成漂卵石地层盾构掘进出渣量三重控制技术和超方后地层空洞的判断方法,可有效控制扳进出渣量并准确判断掘进中是否超方及超方量、超方位置等,为类似工程提供参考依据。

The geological structure of the gravel-boulder foundation is complex and variable, with uneven gradation.It has the characteristics of high water-rich, high strength, low cohesion, poor self-stability, high content of boulders and large particle size.It is difficult to improve the soil during shield tunneling.The torque of the shield cutterhead and the tunneling speed are fluctuating greatly, which makes it difficult to control the amount of slag in the excavation process.The excavation and slag volume will form fbnnation voids, which will cause ground collapse or damage to surrounding buildings and underground pipelines.In this paper, the author systematically analyzes the factors causing the slag discharge and the control measures in the tunnel construction of Chengdu metro gravel-boulder foundation and the formation mechanism of the cavity after exceeding excavation, and summarizes the triple control technology and the formation cavity judgment method for the slag excavation in the drifting pebble stratum.This method can effectively control the amount of slag, and accurately judge the position of the exceeding excavation as well as the possibility of over-excavated amount, which will provide a reference for similar projects.