CHEN Minghao, TANG Ouling, LI Dong, CHEN Xinghai, REN Yun
Journal of Railway Engineering Society. 2025, 42(4): 5-6.
Research purposes: The Quaternary cover layer in the Chengdu area is thick, overlying the red soft rock strata, with a variety of rock and soil types. The unique geological environment has given rise to numerous geotechnical engineering problems, which have constrained the planning and construction of Chengdu rail transit. Through a series of geotechnical engineering practices in Chengdu rail transit construction, this paper systematically analyzes the geological characteristics and causes of various problems and proposes targeted geotechnical investigations of key points and corresponding prevention and control measures.
Research conclusions: (1) The Chengdu rail transit is mainly located in the central part of the Sichuan Basin, which belongs to the Minjiang River watershed. Its geological structures are mainly box-shaped Longquan Mountain anticline, and the basic seismic intensity is Grade Ⅶ. (2) The Chengdu Plain is widely distributed with thick Quaternary Holocene System (Q4) and Pleistocene System (Q3) clay, pebbles, and sand layers, while the cover layers on the hilly and low mountain areas are thinner. The underlying bedrock is the Cretaceous System (K) and Jurassic System (J) red lacustrine sedimentary mudstone, sandstone, etc., with thin layers of gypsum and calcareous halite commonly found in the mudstone. (3) The study area has diverse rock and soil types, and the Chengdu rail transit construction faces large-grained high-strength floating pebbles, lenticular sand layers, Ya'an gravel layers, gypsum-containing formations, shallow gas, red mudstone, composite formations, and hydrogeological problems. The paper provides a detailed explanation of the engineering geological characteristics, geotechnical investigations key points, and control measures for each problem. (4) The research results have reference and guidance significance for the construction of the fifth phase of the Chengdu rail transit and the second phase of the Chengdu suburban railway network.