成都东部新区空港新城咸淡水分布规律研究

Study on the distribution law of salt water in the airport new city in the eastern new district of Chengdu

利用成都高新东区(空港新城)城市地下空间资源地质调查项目实施的188个深度160~220 m钻孔开展分层取样、井液电阻率测试、岩芯分层TDS测试等综合方法查明成都东部新区空港新城咸淡水界面的平面分布特征、垂向分布特征及水化学特征。结果显示:(1)研究区咸淡水界面平面分布呈东西分带特点。(2)从垂向分布特征看,埋深0~15 m范围内,全区基本无微咸水分布;埋深15~20 m范围内,微咸水点零星出现,至埋深20 m后会大量增加;15~70 m埋深内,微咸水普遍分布在地层膏盐分布区,而在非膏盐分布区基本不存在微咸水;在埋深70m以下,丘陵区全区均有微咸水分布的现象。(3)研究区咸水化学成分一般主要以硫酸盐(钠、钙)为主。但在埋深70 m以下非膏盐分布区咸水水化学特征主要以氯酸盐为主,其次为硫酸盐。随着埋深增加,咸水矿化度总体呈上升的趋势,埋深50 m和80 m以下分别出现咸水和卤水现象,但矿化度随深度递增的线性规律并不明显。研究结果为成都东部新区空港新城地下空间利用规划提供基础资料,为广大红层丘陵区查明咸淡水分布规律提供了借鉴。

The horizontal and vertical distribution characteristics and hydrochemical characteristics of the saline and fresh water interface in the east new district of Chengdu were investigated by using 188 boreholes with a depth of 160 ~ 220 m, such as the resistivity test of stratified sampling well fluid and the stratified TDS test of core, which were implemented in the geological survey of urban underground space resources in the east new district of Chengdu( Konggang New City). The results show that:(1) the surface distribution of brackish and fresh water in the study area shows the characteristic of east-west zoning.(2) From the vertical distribution characteristics, there is basically no brackish water distribution in the buried depth of 0 ~15 m in the study area. Slightly brackish water points appear sporadically in the range of 15 ~ 20 m burial depth, and increase greatly when the burial depth reaches 20 m. In the depth of 15 ~ 70 m, brackish water is generally distributed in the gypsum salt distribution area, while there is almost no brackish water in the non-gypsum salt distribution area.(3) The chemical composition of salt water in the study area is mainly sulfate( sodium and calcium), but in the non-gypsum salt distribution area below the burial depth of 70 m, the hydrochemical characteristics of salt water are mainly chlorate, followed by sulfate With the increase of buried depth, salt water salinity rising trend overall, buried depth below 50 m and 80 m respectively in salt water and brine phenomenon, but salinity increasing with depth of linear law is not clear The results for the east new district of Chengdu airport new town underground space use planning provides basic data, for the majority of the red layer hilly ascertain brackish-water distribution provides the reference.