地下车站的混凝土开裂数值分析及抗裂试验研究

针对上海地区富水软土地层中地下车站渗漏水问题,在混凝土开裂原理分析的基础上,建立了地铁车站混凝土结构的有限元损伤模型,揭示了水土荷载作用下混凝土裂缝起裂特点、分布及其发展规律.采用光栅光纤监测技术开展了混凝土温度-应变现场实验,得到了在施工全过程中混凝土结构的温度及应变变化规律,分析了温度、养护时间、抗裂剂等因素对混凝土开裂的影响.研究表明:根据形态特点,裂缝可分为贯通裂缝和非贯通裂缝,其中贯通裂缝可引起车站结构渗漏水.由于约束作用,贯通裂缝主要发生在侧墙靠近中板和底板的位置.添加抗裂剂、延长养护时间可有效提高混凝土抗裂性能和防水抗渗性能.

Numerical analysis and experimental study on concrete cracking of underground station

For the leakage problem of underground station in water-rich soft soil layer in Shanghai and based on the analysis of concrete cracking principle, the finite element damage model of concrete structure of subway station is established. It reveals the characteristics of concrete crack initiation, the distribution and development law of concrete cracks under load of soil and water. In this paper, the temperature-strain field experiment of concrete is carried out by using fiber grating monitoring technology, and the temperature of concrete structure and law of its strain variation in the whole process of construction is obtained. Impact analysis of the temperature, maintenance time, anti-crack agent and other factors is made on the issue of the concrete cracking. The research shows that there are through and non-through cracks according to their morphological characteristics, in which the through cracks can cause the leakage of the station structure. Because of the constraints, the through-crack mainly occurs in the sidewall near the middle plate and soleplate. Adding anti-crack agent and prolonging maintenance time can effectively improve concrete crack resistance and waterproof impermeability.