重庆市主城辖区内铜锣山地区可溶岩主要分布在铜锣峡背斜和南温泉背斜中心地带, 以三叠系下统嘉陵江 组、中统雷口坡组碳酸盐岩为主, 岩溶发育的主要特征为顺层性、垂直分带性和不均匀性, 上覆土层为透水- 阻水型 二元结构盖层。研究区内地面塌陷主要为自然状态下岩溶坍塌及人类工程建设活动引发的塌陷两种, 自然条件下 塌陷为个别产生, 人为因素导致的塌陷则成群出现, 塌陷群的分布特征主要受可溶岩的分布、岩溶发育程度和塌陷 诱发因素的控制。研究区岩溶塌陷分布主要集中于: ( 1) 槽谷中地势低洼地带; ( 2) 出露岩层为可溶碳酸盐岩且岩溶 发育的地区; ( 3) 土层覆盖层厚度3~ 10 m 的地区; ( 4) 地下水位急剧下降地区。地面塌陷成因为/ 潜蚀软化- 渗透 破坏- 负压吸蚀0 致塌。此外, 隧道开挖切穿含水层导致地下水位迅速下降是诱发地面塌陷的关键环节。

Karst ro cks in To ng luoshan o f Cho ng qing city ar e mainly distr ibuted in the heartland of the To ng luox ia Anticline and Nanw enquan Ant icline, and are mostly the carbonate o f t he Lower T riassic Jialing jiang Formatio n and Middle T riassic Leiko upo Formatio n. The kar st r ocks H dev elo p alo ng t he st rata lay ers unev enly and are char acter ized by v ertical zonatio n, and t he over ly2 ing str at um o n the karst ro cks has a Hdual st ructur eH consist ing of the upper permeable lay er and low er imperv ious layer . Tw o types o f karst collapse dominate in t he study ar ea including the natural co llapse and man2made co llapse, and the nat ur al collapse occur s independently w hile t he man2made co lla pse usually occurs in g r oups. T he distr ibution o f kar st co llapse is affect ed by the distr ibut ion of kar st rock, kar st development, and inducing facto rs. Ka rst collapse in T ongluo shan o f Cho ng qing city is ma inly located in( 1) low2ly ing ar eas in the tro ugh v alley; ( 2) carbonate outcrops w ith karst development; ( 3) ar eas cov er ed by so il layer s wit h thickness o f 3 to 10 meters; and( 4) areas with sig nificantly decreasing gr oundw ater levels. H Gro und collapse in study ar ea is mainly caused by / H subsur faceH erosion and H softeningH2H seepage failureH2H negative pr essureH abso rption0 . Mo reov er, sudden decline in g ro undwater levels resulted from tunnel excav ation thro ug h aquifer is the key o f collapse develo pment.

重庆市国土房管局2011 年度地质灾害防治专项资金资助项目( 120301)