金沙江白鹤滩水电站旱谷地料场岩溶发育特征及工程效应

Karst Development Characteristics and Engineering Effects of the Hangudi Quarry of Baihetan Hydropower Station,Jinsha River

巧家县旱谷地石灰石料场岩溶总体不发育,但开挖揭示有较大岩溶管道,查明岩溶发育的规律对料场下一步开采布局具有现实意义。通过对料场及其周边的实地调查、钻孔揭露及物探,对地下岩溶以及地表岩溶分布特征及位置进行统计,结合构造、岩性、水文及地貌等地质特征对岩溶发育机理进行分析讨论,认为特殊水文条件下可以在岩溶发育较差地区发育岩溶异常带"。主要结论如下:①巧家旱谷地斜坡由于地表支沟发育,地表水无法聚集,地表岩溶不发育。②料场上方缓坡平台后缘有一断层泉,流量约1. 8 L/s,泉水出露后又在该平台渗入地下,使得料场区地下岩溶较地表发育;旱谷地平台后缘保存有菩萨洞和蝙蝠洞,为当时溶洞的出口。③地下岩溶通道首先在普家村平台断层泉渗入地下,沿中梁子沟发育切层陡倾坡外的"垂直"管道,直径约12 m,在1 400 m高程,顺层发育水平管道(层控),并在大弯子沟右岸菩萨洞及蝙蝠洞岩溶水排出地表;随着旱谷地台面的抬升,现今岩溶管道仍然以垂直管道向金沙江谷底方向排泄,出口在巧家县城龙潭一带。④由于管道及其附近塌陷及溶洞角砾、次生泥充填,危岩垮塌严重,不能满足石料质量要求,料场区有用料储量减少10%~15%。

The Karst of the limestone yard in Hangudi of Qiaojia County is poorly developed,but excavation reveals that there exists large Karst pipelines. It will be significant to find out the law of Karst development for the next mining layout of the material yard. The distribution characteristics and location of underground Karst and surface Karst were analyzed through field investigation,drill hole and geophysical prospecting in and around the material yard,and combined with the study of geological characteristics such as structure,lithology,hydrology and geomorphology,the mechanism of Karst development was analyzed and discussed,it is considered that the areas can develop Karst anomaly zone in poor Karst development,under special hydrological condition. The results show there as follows.① Due to the development of surface tributaries,the surface water can not be gathered,and the surface karst is not developed.② There is a fault spring at the trailing edge of the gentle slope platform above the material yard with a flow rate of about 1. 8 L/s,and the spring water seeps into the underground of the platform,which makes the underground Karst caves of the material yard area are more developed than the surface;The Buddha Cave and the Bat Cave were preserved on the trailing edge of the Hangudi Platform,which was the exit of the Karst caves at that time.③ The underground Karst passage first seeps into the underground in the fault spring of Pujia Village platform. The spring infiltrates into the ground and develops a "vertical"pipeline outside the steep slope of the cut-out slope along the Zhongliangzi groove,whose the diameter is about 12 m. At the location of 1 400 m elevation,horizontal pipelines are developed along the bedding layer,and the Karst water is discharged to the surface from Buddha Cave and Bat Cave on the right bank of the Dawanzi groove. With the uplift of the Hangudi platform,the Karst pipelines are still discharged to the bottom of the Jinsha River by vertical pipelines,and the exit is in the Longtan area of Qiaojia County.④ Due to the collapse of the pipeline and its vicinity,which filling of Karst cave breccia and secondary mud,so the quality requirements of stone cannot be met,and the reserves of useful materials in the material yard area are reduced by about 10%~ 15%.