Key techniques in geotechnical treatment of a large karst depression for FAST
Xu Ming1 Song Erxiang1 Shen Zhiping2,3 Zhu Boqin4 Yan Jinkai5#br#
Nie Yueping6 Wu Bin2,3 Wang Hong2,3 Fu Junyi2,3
1. Tsinghua University, Beijing 100084, China; 2. Guizhou Zhengye Engineering and Investment Incorporation Limited, Guiyang 550012, China;
3. Guizhou Karst Foundation Engineering Technology Research Center, Guiyang 550012, China; 4. National Astronomical Observatories, CAS,
Beijing 100012, China; 5. China Institute of Geo-environment Monitoring, China Geological Survey, Beijing 100081, China;
6. Institute of Remote Sensing and Digital Earth, CAS, Beijing 100094, China
Abstract：FAST (five-hundred-meter aperture spherical telescope) is constructed in a large karst depression with very complex geological and hydraulical conditions. Despite immense difficulties in geotechnical engineering, great success has been achieved with a number of novelties: (1) a method is proposed to identify the optimal coordination of the excavation center, which leads to a minimum construction cost as well as minimum impact on environment; (2) a new retaining structure supporting rock blocks is adopted, with a method being proposed to calculate the active earth pressure of rock blocks based on DEM simulation; (3) the influence of slope shape on its stability is analyzed using FEM strength reduction method, and the influence of cable tension on the slope stability is also investigated; (4) the static and dynamic stability of two super-high rock slopes is analyzed using UDEC, based on which proper remediation work is taken; (5) based on the geological and hydraulical conditions of the karst depression, a drainage tunnel is constructed to prevent flooding along with the natural karst pipeline flow. These achievements have been used successfully in FAST, which can provide reference for the construction of Chinese telescope infrastructure.
