锦屏水电站洞室群衬砌裂缝成因分析

Analysis of Tunnel Lining Cracks of Jinping Hydropower Station

针对锦屏一级水电站左岸各高层洞室均出现衬砌裂缝现象,首先调查统计裂缝信息(裂纹编号、素描、开度测量(用金属塞尺测量,精度0.02mm)、描述记录),结合隧洞部位地质条件、边坡和隧洞监测成果、施工因素、现场调查情况,系统分析裂缝成因。研究认为:左岸拱肩槽开挖卸荷作用是衬砌致裂的主要因素,而施工因素、衬砌砼(自身)产生的各种物理作用等因素也会有一定致裂作用。而洞室监测资料说明大部分围岩变形趋向于收敛且对左岸边坡整体稳定性无不利影响。

This paper firstly investigated and counted the crack information including crack numbers, sketch, opening measure （with a metal feeler, precision 0.02 mm） and description and record, aiming at the lining crack phenomenon which each high-rise tunnel of left bank in Jinping first.rage hydropower station appears. Combining with geological conditions and slope of tunnel parts and results of tunnel monitoring, construction factors, field investigation, the causes of cracks were systematically analyzed. The study shows： the main factor of lining cracks is the effect of unloading of excavation of left abutment, however, the various physical function which produced by construction factors and lining concrete （itselt） also have certain effect of leading to crack. The monitoring data of tunnel shows that most surrounding rock deformation tends to convergence and has no adverse effect to the overall stability of left slope.