考虑水压力情况下地铁管片混凝土的硫酸盐侵蚀试验与分析

发布时间：2018-06-29 23:48

本文选题：地铁管片混凝土 + 水压力　；参考：《华南理工大学》2014年硕士论文

【摘要】：目前，我国建有大量地铁隧道。地铁管片混凝土是一种典型的多孔介质，外部环境的硫酸盐通过孔隙扩散到混凝土内部并与其中某些矿物成分发生反应，使得管片的力学性能发生劣化。地铁隧道深埋地下，，地下水压力的存在可能加速硫酸盐的侵入，促使管片劣化更快。为了探讨有水压力情况下硫酸盐对地铁管片混凝土的侵蚀作用，本文开展了如下工作： 1、针对地铁管片混凝土立方体试块和圆柱体试块，开展了其在无水压力的硫酸钠溶液中浸泡30、60、90、120、150天之后的抗压强度和硫酸根离子浓度试验。研究表明：（1）随着浸泡时间的增加，管片混凝土的抗压强度呈现先增后减的变化趋势，浸泡60天后达到最大值（；2）随着深度的增加，管片混凝土内部的硫酸根离子浓度迅速减小，且在深度1.5mm和4.5mm之间出现陡降；（3）对应相同深度，圆柱体内部的硫酸根离子浓度相比立方体略高。 2、针对地铁管片混凝土立方体试块和圆柱体试块，开展了其在5m、10m、15m水压力的硫酸钠溶液中浸泡30、60、90、120、150天之后的抗压强度和硫酸根离子浓度的试验。研究表明：（1）与无水压力情况相比，上述水压力并未就硫酸盐对地铁管片混凝土的侵蚀作用产生明显影响；（2）本文所用压力装置不仅构造简单，而且压力稳定。 3、对Tixier R扩散模型进行了改进，并利用其模拟硫酸根离子在地铁管片混凝土中的扩散过程，将模拟结果与试验结果进行了对比。研究表明：改进后的扩散模型可较好地再现硫酸根离子在管片混凝土中的扩散行为。 4、假设硫酸盐侵蚀后管片混凝土的抗压强度是硫酸根离子浓度的特定函数，提出了侵蚀后管片混凝土抗压强度计算模型，将计算结果与试验结果进行了对比。研究表明：采用该模型计算得到的侵蚀后管片混凝土抗压强度与试验结果吻合较好。
[Abstract]:At present, our country has a large number of subway tunnels. Subway segment concrete is a kind of typical porous medium. The sulphate in the external environment diffuses into the concrete through the pore and reacts with some mineral components in the concrete, resulting in the deterioration of the mechanical properties of the segment. The existence of groundwater pressure may accelerate the invasion of sulphate and accelerate the deterioration of segments. In order to study the erosion effect of sulfate on the concrete of metro segment under water pressure, the following work has been carried out in this paper: 1. The compressive strength and the concentration of sulfate ion were tested after soaking in the solution of sodium sulfate under anhydrous pressure for 30 ~ 60,90120150 days. The results showed that: (1) with the increase of soaking time, the compressive strength of segment concrete increased first and then decreased, and reached the maximum after 60 days of immersion. The concentration of sulfate ion in segment concrete decreases rapidly, and there is a sharp drop between the depth of 1.5mm and 4.5mm. (3) the same depth is corresponding to the concentration of sulfate ion. The concentration of sulfate ion in the cylinder is slightly higher than that in the cube. 2. The compressive strength and the concentration of sulfate ion in sodium sulfate solution at water pressure of 5 m ~ 10 m ~ (15 m) were tested after immersion for 30 ~ 60,90120150 days. The results show that: (1) compared with the case of anhydrous pressure, the water pressure has no obvious effect on the erosion effect of sulfate on the concrete of subway segments, (2) the pressure device used in this paper is not only simple in construction, And the pressure is stable. 3. The Tixier R diffusion model is improved, and the diffusion process of sulfate ion in concrete is simulated. The simulation results are compared with the experimental results. The results show that the improved diffusion model can reproduce the diffusion behavior of sulfate ion in concrete segments. 4. Assuming that the compressive strength of the concrete after sulfate erosion is a specific function of the concentration of sulfate ion. A model for calculating the compressive strength of corroded segment concrete is proposed, and the calculated results are compared with the experimental results. The results show that the compressive strength of the corroded segment concrete calculated by this model is in good agreement with the experimental results.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U231;U454

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