西南典型紧窄褶皱小尺度浅层岩溶水系统特征及隧道涌水分析

西南地区典型紧窄褶皱控制下的浅层岩溶水，具有循环交替快、水量丰富等特点。精细刻画小尺度浅层岩溶水系统模式类型及其特征，对于探讨岩溶水资源量以及中—浅埋隧道涌水条件具有重要意义。本文以西南典型紧窄褶皱——重庆铜锣山背斜和遵义铜锣井背斜为研究对象，细致地梳理岩溶水系统特征的控制性因素，提出地层空间结构的细微差异导致含水介质及地下水补给、径流、排泄特征等不尽相同。据此，将研究区浅层岩溶水系统细分为四类小尺度模式，并基于各模式差异分析中—浅埋隧道涌水条件。研究认为：穿越不同小尺度岩溶水系统的隧址段，其涌水条件具有一定差异；间互式地层空间结构导致小尺度浅层岩溶水系统之间因地表水体的转换而存在联系，计算涌水量时需考虑相邻可溶岩地层外源补给，而包裹式结构则造成各系统相对独立，计算时需考虑相邻非可溶岩地层外源补给；深切河谷排泄边界，不可忽略降雨对隙流散排型模式的补给，计算涌水量时，降雨量参数应小于年均降雨量，但若边界为浅切河谷，降雨量参数可直接选用年均降雨量。

Analysis on the characteristics of small-scale shallow karst water systems in typical tight-narrow folds and tunnel water inrush in southwestern China

In southwest China, shallow karst water, under the control of typical tight-narrow folds, has the characteristics of quick cyclic-alternating pattern and abundant groundwater resource, etc. It is of great significance to describe the pattern types and their characteristics of small-scale shallow karst water systems in order to discuss karst water resource and water inrush condition in medium-shallow buried tunnels. Taking two typical tight-narrow folds (Tongluoshan anticline in Chongqing and Tongluojing anticline in Zunyi)as the study objects, in this paper, we collate the controlling factors of karst water systems characteristics in detail, and point out that the subtle differences of stratum structure lead to different water-bearing media, and the characteristics of groundwater recharge, run-off and discharge. According to these differences, shallow karst water systems are divided into four small-scale patterns in research area. In addition, based on the differences of four patterns, water inrushing conditions of medium-shallow buried tunnel are analyzed qualitatively. The research results show that， (1)There are some differences in water inrushing conditions, when tunnel cuts through different small-scale karst water systems.(2)The connection among small-scale shallow karst water systems is existed through the transformation of surface water, due to the opposite spatial structure of strata, in the calculation of water flow, the exogenous recharge from adjacent soluable karst aquifers should be taken into account, while the encapsulated spatial structure of strata makes each system relatively independent, in the calculation of the water flow, the exogenous recharge from adjacent clastic karst aquifers should be taken into account.(3) Meanwhile, the recharge share of fracture-flow dispersed discharge type from rainfall cannot be ignored when the discharge boundary is deep valley, thus in the calculation of water flow,the recharge should be less than average annual precipitation. However, if the discharge boundary is shallow valley, the recharge is nearly equal to average annual precipitation.