一、概述1972年动工兴建、面积为二万米~2的某八层楼房,座落在桂西北的一个溶洞内。该溶洞长250米,宽60～80米,高37米,南北各有一洞口,洞底有一条地下河(图1)。1.洞室工程地质条件洞顶岩体完整,厚56～117米,约等于洞室高度的3～4倍,洞顶呈半圆形自然拱。 I. An overview of the construction of an eight-story building with an area of ​​20,000 meters to 2 to be built in 1972. It is located in a cave in northwestern Guangxi. The cave is 250 meters long, 60 to 80 meters wide and 37 meters high. There is an opening in the north and south, and there is an underground river at the bottom of the cave (Figure 1). 1. Cave engineering geological conditions The rock mass on the top of the cavern is intact, with a thickness of 56 to 117 meters, approximately equal to 3 to 4 times the height of the cavern. The top of the cave is a semi-circular natural arch.