水利小断面土质围岩隧洞双浆液换拱施工技术

Construction Technology of Double Grout Arch Change for Hydraulic Light-section Soil-based Surrounding Rock Tunnel

广西驮英灌区客兰东干渠竹琴2#隧洞KD23+620.134-KD24+302进口浅埋段隧洞因持续性强降雨渗入地表导致洞身土质围岩软化,洞内大面积渗水严重,致使已完成初支的洞身局部侧墙初支开裂脱落、钢拱架爆裂。对渗水变形机理进行分析,提出渗水治理、双浆液固化围岩、增设超前小管棚及换拱重做等综合性治理措施,确保了工期,取得了良好的经济效益和社会效益。本文重点介绍水利小断面浅埋土质围岩隧洞渗水变形双浆液换拱施工工艺及控制措施。

The tunnel at the entrance of the shallowly buried section of Zhuqin No.2 KD23+620.134〜KD24+302 tunnel of trunk canal in Kelan East,Tuoying Irrigation District,Guangxi Province is analyzed.The long-time continuous heavy rainfall penetrates into the ground,contributing to the softening of the soil-based surrounding rock of the tunnel body,and the large-area serious water seepage inside the tunnel,thereby resulting in the cracking and falling off of local side walls of the tunnels with completed initial support,and the bursts of the steel arch.Through the analysis of seepage deformation mechanism,the comprehensive governance measures are put forward,including seepage treatment,double grout solidification of surrounding rocks,adding advanced small pipe sheds to control deformation and arch change for reconstruction,which ensure the construction period and obtain good economic and social benefits.The construction technology of double grout arch change for seepage deformation of hydraulic light-section soil-based surrounding rock tunnel in the shallowly buried section is introduced in particular.