崇左岩溶峰林区岩溶发育特征及对钻孔涌水量的影响

【目的】研究崇左岩溶峰林区岩溶发育规律及对钻孔涌水量的影响,深化对崇左岩溶峰林区岩溶水文地质条件的认识,更好地指导今后在该地区开展地下水资源开发利用。【方法】通过对崇左岩溶峰林区128个钻孔的深度、涌水量、岩溶发育特征等指标进行统计分析,总结该区岩溶发育规律及影响因素,并研究其对钻孔涌水量的控制作用。【结果】研究区最小钻井深50.02m,最大井深121.80m,平均深度为94.04m。成井86口,成井率为67.18%,有68.53%的钻井涌水量分布于100～400 m~3/d。钻孔遇洞率为75.78%,平均线岩溶率为5.01%。在0～100m内均有溶洞发育,100m以下未见溶洞发育。0～60m深度段岩溶较发育,溶洞高度为441.57m,占总高度的80.41%,线岩溶率(5.42%～12.91%)大于平均线岩溶率;但0～40m深度段内溶洞全部或部分被充填,供水意义不大,而在40～60m深度段溶洞填充率小。【结论】在该地区通过机井解决缺水问题的条件比较有利,机井井深不超过100m为宜;40～60m深度段是本区主要出水段。由于钻孔均部署在地下水的补给区,或位于岩溶发育相对较弱的地区,钻孔中溶洞主要以小型溶洞(小于等于2m)为主,大型溶洞(大于2m)较少。这种水文地质条件和溶洞发育特征,导致研究区大部分钻孔(68.53%)的涌水量分布于100～400m~3/d。

Characteristics of Karst Development and Its Impact on the Yields of Wells in Karst Peak Forest Region in Chongzuo City,Guangxi

[Objective] In order to deepen the understanding of the karst hydro-geological conditions and better guide the development and utilization of groundwater resources in karst peak forest area of Chongzuo city in the future,the karst development law and its impact on the yields of wells was studied in this paper.[Methods] Through the statistical analysis of the depth,in flow of water and karst development characteristics from 128 boreholes,the karst development law and influencing factors were summarized,and its controlling impact on the yields of wells was studied in karst peak forest area of Chongzuo city.[Results] The minimum depth of borehole in the study area was 50.02 m,the maximum well depth was 121.80 m,with an average depth of 94.04 m.Of which 86 boreholes could be used as water wells with a standard water in flow,with the successful rate of 67.18%,and there were 68.53% wells with the drilling water in flow distributing between 100 m³/d and 400 m³/d.The rate of reaching holes when drilling was 75.78%,and the average line karst rate was 5.01%. The caves were all developed in the range of 0~100 m depth,and no caves were found below 100 m depth. The karst was more developed in the depth range of 0~60 m,and the height of the cave was 441.57 m,accounting for 80.41% of the total height. The line karst rate (range 5.42%~12.91%) was larger than the average line karst rate. However,all or part of the cave in the 0~40 m depth were filled with little significance to water supply,while the filling rates in the depth of 40~60 m was small.[Conclusion] It is more advantageous to solve the problem of water shortage through the well in the area. The well depth should not exceed 100 m and the 40~60 m depth is the main water discharge section in this area. Since the boreholes are all deployed in the recharge area of groundwater or in areas with relatively weak karst development,the caves in boreholes are mainly small caves (less than or equal to 2 m) and large caves (greater than 2 m) are fewer. This hydrogeological condition and karst development characteristics cause the water inflow in most of the boreholes (68.53%) in the study area to be distributed between 100 m³/d and 400 m³/d.