龙游牛场古工程洞室群变形破坏调查及工程地质条件分析

摘要

建于南宋的龙游牛场古洞室是国保单位小南海石室(即龙游石窟)的重要组成部分.这一由两个古洞室组成的洞室群,因开挖年代悠久,并因具有罕见的“边墙-顶板斜撑结构”(2号洞)和“塞式支顶结构”(1号洞)而引人关注.但两洞(包括洞口边坡)的变形破坏都十分严重.为长期保护这一重要的不可移动文物,作者从工程地质条件分析入手,对发生的严重变形破坏作了详细的调查分析.分析表明,长期风化(特别是生物风化)和由缓倾角红层构成的顶板过薄等是造成牛场古洞室发生较严重变形破坏的主要原因.%Niuchang ancient underground Caverns in City Longyou were built in Southern Song Dynasty and is an important part of national key cultural relics protection unit from Xiao Nanhai cave(the Longyou Grotto).They have old excavation history,rare slanting sidewall-roof structure in No.2 Cavern and plug topside structure in No.1 Cavern.The two cavern chambers get great attentions.But,serious deformation and failure happen in their roofs and slopes at the entrances of both caverns.In order to preserve the relics,this paper has carried a detailed investigationand analyzation about deformation and failure from aspect of engineering geological conditions.It shows that the long-term weathering,especially biological and thin roof composed of gentle-dip red clastic rocks are the main reasons of their deformation and failure.