盾构同步注浆复合水泥基—水玻璃双液浆材料特性研究及强度模拟试验

发布时间：2018-08-11 21:24

【摘要】：盾构法因其安全高效、优质环保的特点,已经成为隧道工程领域的主流工法之一。同步注浆作为盾构推进过程中的重要工序,对于地表沉降控制、缓解围岩变形等至关重要。目前同步注浆材料主要分为单液浆和双液浆,总体看来,水泥-水玻璃双液浆胶凝时间短、早期强度高,在软土地层和富水地层盾构施工中得到了广泛应用。但传统水泥-水玻璃双液浆耐久性差,抗水溶蚀能力差,而且成本高。在传统水-水玻璃双液浆的基础上,复合水泥基-水玻璃双液浆用粉煤灰和矿渣代替部分水泥掺入,利用碱激发粉煤灰和矿渣活性的特点,最终形成由低CaO/SiO2的C-S-H胶凝体和耐久性很好的无定形类沸石类物质共同构成的密实体结构,有效提高了双液浆耐久性,同时降低了成本。本文开展了浆液特性试验,研究了粉料比例、水玻璃掺量、水灰比对复合水泥基-水玻璃双液浆流动性能、稳定性能、胶凝性能的影响规律,总结出适合盾构隧道同步注浆施工的最优配合比。同时,还研究粉料拌合方式对新拌A浆液性能的影响和养护条件对结石体抗压强度的影响。此外,将双液浆环状结石体置于模拟地层中养护,探究了复合水泥基-水玻璃双液浆在实际地层中的强度发展规律。研究结果表明:(1)粉煤灰和矿渣代替部分水泥掺入,双液浆的流动度降低约10%,早期强度降低10%～15%,但是胶凝时间延长40%～80%,A浆液泌水率降低32%。水玻璃掺量为0.25～0.3时,双液浆流动性能较好,胶凝时间容易控制,结石体抗压强度高。水灰比增大,双液浆流动性增强、胶凝时间延长,但是抗压强度和稳定性有所降低。(2)粉料拌合时,二次添加拌合水会导致A浆液泌水率增加约15%,流动性增强;二次添加粉料会导致A浆液泌水率减小约20%,流动性增强。在满足工程泌水率要求(5%)的前提下,二次添加拌合水更有利于A浆液的流动性能改善。(3)利用幂函数拟合曲线,可以得到复合水泥基-水玻璃双液浆的回弹测强曲线,相对误差在10%以内,且相关系数为0.74,相关性良好,以此可以确定复合水泥基-水玻璃双液浆的回弹值与抗压强度之间的关系。环状结石体在模拟地层中养护,7d时抗压强度为12.5MPa,56d时抗压强度达到28.6MPa,能够很好地满足盾构隧道同步注浆要求。
[Abstract]:Shield method has become one of the main engineering methods in tunnel engineering field because of its safety and efficiency, high quality and environmental protection. Synchronous grouting, as an important procedure in shield tunneling, is very important for controlling surface subsidence and alleviating surrounding rock deformation. At present, the synchronous grouting materials are mainly divided into single slurry and double liquid slurry. In general, the cement-water glass double liquid slurry has short gelation time and high early strength, so it has been widely used in shield construction of soft soil layer and water-rich ground layer. But the traditional cement-water glass double-liquid slurry has poor durability, poor water dissolution resistance and high cost. On the basis of traditional water-water glass double liquid slurry, composite cement base water glass double liquid slurry uses fly ash and slag instead of some cement, and uses alkali to excite fly ash and slag activity. Finally, a dense solid structure composed of C-S-H cementitious with low CaO/SiO2 and amorphous zeolites with good durability is formed, which effectively improves the durability of double liquid slurry and reduces the cost. The effects of powder ratio, water glass content and water / cement ratio on the fluidity, stability and cementing properties of composite cement-based water glass double slurry were studied in this paper. The optimal mix ratio suitable for synchronous grouting construction of shield tunnel is summarized. At the same time, the influence of powder mixing mode on the performance of fresh A slurry and the influence of curing conditions on the compressive strength of stone body were also studied. In addition, the double liquid slurry annular stone body was put into the simulated formation and the strength development law of the composite cement base and water glass double liquid slurry in the actual formation was investigated. The results are as follows: (1) when fly ash and slag are added in place of some cement, the fluidity and early strength of double slurry decrease by about 10 and 10 / 15 respectively, but the gelation time is prolonged by 40% and 80%, and the bleeding rate of slurry decreases by 32%. When the amount of water glass is 0.25o 0.3, the fluidity of double slurry is better, the gelation time is easy to control, and the compressive strength of stone is high. With the increase of water-cement ratio, the fluidity and the gelation time of the two-liquid slurry increased, but the compressive strength and stability decreased. (2) when the powder was mixed, the secondary mixing water would increase the bleeding rate of A slurry by about 15%, and the fluidity would increase; The secondary addition of powder will reduce the bleeding rate of A slurry by about 20% and enhance the fluidity. On the premise of meeting the requirement of engineering bleeding rate (5%), the secondary mixing water is more favorable to improve the fluidity of A slurry. (3) by using the power function fitting curve, the rebound strength curve of compound cement base and water glass double liquid slurry can be obtained. The relative error is less than 10%, and the correlation coefficient is 0.74, so the relationship between the rebound value and the compressive strength of the composite cement-based water glass double slurry can be determined. The compressive strength of annular stone is 28.6MPa when it is maintained in simulated stratum for 7 days, and the compressive strength is 12.5 MPA / 56d, which can meet the requirement of synchronous grouting in shield tunnel.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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