西延高铁隧道排水系统结晶堵塞机理研究

Crystallization Blockage Mechanism in Drainage System of Xi'an-Yan'an HSR Tunnel

基于西延高铁隧道的排水系统结晶堵塞现场勘察与调研情况,以宜君隧道和武家塬隧道为例,对地下水、结晶物、喷混凝土外层渗水、建筑材料等取样分析,明确结晶物的主要组分与形成机理。研究表明,白、灰色结晶沉淀物堵塞位置主要位于环向盲管出水口,管口水流小,堵塞严重,白色结晶物的主要成分为CaCO_(3),少量灰色结晶为掺杂混凝土的碳酸盐,结晶物中Ca^(2+)主要来自喷射混凝土中水泥的水化产物,CO_(3)^(2-)主要来源于地下水中的矿化离子。因此,隧道排水管中结晶过程包括3个阶段:地下水对喷射混凝土的渗透过程;混凝土中钙的溶出过程;排水管中的晶体沉积过程,为隧道排水系统结晶堵塞灾害的预防和治理提供理论基础。

Based on the on-site survey and investigation of crystallization blockage in the drainage system of Xi'an-Yan'an HSR Tunnel,taking Yijun Tunnel and Wujiayuan Tunnel as examples,this paper samples and analyzes groundwater,crystals,shotcrete outer layer seepage and building materials,and clarifies the main components and formation mechanism of crystals.The study shows that the blockage position of white and gray crystalline deposits is mainly located at the outlet of the circumferential blind pipe,with small water flow at the nozzle and serious blockage.The main component of white crystal is CaCO_(3),and a small amount of gray crystal is carbonate mixed with concrete.In the crystal,Ca^(2+) mainly comes from the hydration product of cement in shotcrete,and CO_(3)^(2-)mainly comes from mineralized ions in groundwater.Therefore,the crystallization process in tunnel drainage pipe includes 3 stages:penetration process of groundwater to shotcrete;dissolution process of calcium in concrete;crystal deposition process in drainage pipe,which provides a theoretical basis for prevention and treatment of crystallization blockage hazards in tunnel drainage system.