成昆新线成峨段地下水化学特征及侵蚀性研究

Study on Groundwater Chemical Characteristics and Erosion in ChengduEmei Section of Chengdu-Kunming Railway Line

研究目的:铁路工程地下水是否具有侵蚀性直接关系到工程投资、工程耐久性和安全,而地下水的侵蚀性与其化学特征密切相关。成昆铁路新线成峨段大部分段落位于平原地区,地下水位高,地下结构不可避免的要与地下水接触。通过对地下水取样进行简分析和侵蚀性试验,查清其化学特征、成因、分布及侵蚀性。研究结论:(1)成峨段地下水中Ca^(2+)、SO_4^(2-)、HCO_3^-含量较高,Mg^(2+)、K^+、Na^+、Cl^-含量较低;(2)Ca^(2+)、SO_4^(2-)及矿化度的高值区主要分布于石膏较发育的K 0+000~K 80+000段,pH值沿线路走向数值高低分布较均匀,侵蚀性CO_2的含量数值高低分布不均匀、无规律;(3)K0+000~K 0+080段地下结构工程应提高混凝土抗硫酸盐侵蚀的能力,K 7+800~K 9+500、K 12+600~K 13+500、K 63+000~K 63+900共3个段落应提高抗氯盐侵蚀的能力,全线地下结构工程应提高抗酸性侵蚀和抗侵蚀性CO_2侵蚀的能力;(4)本研究成果可为该段铁路地下结构工程抗腐蚀提供地质依据和防护措施,也可供同类工程勘察设计借鉴。

Research purposes： Whether groundwater of railway engineering is the erosion or not is directly related to the project investment, project durability and safety, and the groundwater erosive is closely related to its chemical characteristic. Most of sections of Chengdu - Kunming railway line are in the plains, underground water level is high, the underground structure is inevitable to contact with the ground water. Through the groundwater sample analysis and corrosive test, its chemical characteristic, cause, distribution and erosion are found out. Research conclusions： （ 1 ） Ca2 ~ , SO^- ~11 HCOf content is higher in groundwater, Mg2 ~ , K ＋ , Na ~ ~ C1 - content is lower. （2） Ca2＋ , SO^- and the high value area of mineralization are mainly distributed in the gypsum from the development of K 0 ＋ 000 - K 80 ＋ 000 m section, PH level along the road towards the numerical distribution is uniform, the distribution of corrosive CO2 content value is uneven and irregular. （ 3 ） K 0 ＋ 000 - K 0 ＋ 080 m underground structure engineering should improve the ability of concrete sulfate attack resistance ; The three sections of K 7 ＋ 800 K 9 ＋500, K 12 ＋600 -K 13 ＋500 and K 63 ＋000 - K 63 ＋900 m should improve the ability of resistance to chlorine salt erosion; All underground structure engineering should improve acid erosion and erosion resistance ability of CO2 corrosion. （4）This research result can provide the reliable geological basis and protection measures for corrosion for the segment railway underground structure engineering, also can be used for similar engineering survey and design.