新型单液惰性浆性能优化试验及体积收缩规律研究

发布时间：2018-12-18 02:18

【摘要】：盾构工法已广泛应用于城市地铁及重大过江隧道的修建。然而,盾构施工导致的地层损失、地表的变形沉降始终是困扰专家学者的重大难题。同步注浆是减小地层损失、控制地层应力释放和地层变形的重要手段,是盾构施工的必备及关键工序。当前关于盾构隧道同步注浆的研究主要集中在数值模拟方面,对注浆参数的选取过分依赖于工程技术人员的个人经验,具有一定的局限性。对浆液在硬化的过程中的变形规律认识也仍不明确。因此本文结合上海苏州等软土、复合地层盾构隧道所采用的新型单液惰性浆液,进行了室内配比优化实验,在此基础上还探究了搅拌时间、搅拌方式对浆液性能的影响;并且通过分析浆体的受力状况研制了浆液收缩变形装置,研究了新型单液惰性浆体在注浆压力下的收缩变形规律。主要研究内容如下:(1)借鉴上海苏州等软土、复合地层盾构隧道所采用的新型单液惰性浆液配方,采取均匀试验的设计方法,进行了同步注浆材料的配比优化,为工程上采用合适的浆液配比提供科学的依据。并通过多元非线性回归探讨了浆液各组分对浆液某些施工性能的具体影响。(2)在研究浆液性能随浆液组分变化规律的基础上,以满足强度要求R281.OMpa为前提采用MATLAB SQP优化方法对新型单液惰性浆液进行了配比优化,结果如下:熟石灰120g、粉煤灰574.4g、膨润土 203.4g、砂1015.3g、水684.7g、减水剂5g。(3)在优化配比的基础上研究搅拌时间、搅拌速度、搅拌杆类型对浆液各项性能的影响,高速(800r/min)搅拌相比于低速(200r/min)搅拌状态时浆液稠度值增大10%左右、泌水率下降30%、28d抗压强度值下降10%。(4)研制了浆体收缩变形实验装置,比较系统地研究了浆液注入盾尾空隙后浆体的变形规律,探讨了不同浆液类型、不同注浆压力、不同地层基础对浆体变形规律的影响。浆液体积收缩率随着时间的增大而逐渐增大,相同注浆压力下浆液的体积收缩率增长幅度成倍减小;相比于黏土土质,浆液在砂土土质中体积收缩变形速率更快,且最终形变量较大。
[Abstract]:Shield method has been widely used in the construction of urban subway and major cross-river tunnel. However, the formation loss caused by shield tunneling and the deformation and settlement of the ground surface have always been a major problem for experts and scholars. Synchronous grouting is an important means to reduce formation loss and control formation stress release and formation deformation. It is also a necessary and key procedure in shield construction. At present, the research on synchronous grouting in shield tunnel is mainly focused on numerical simulation. The selection of grouting parameters depends too much on the personal experience of engineers and technicians, and has some limitations. The understanding of the deformation law of slurry during hardening is still unclear. In this paper, combined with the soft soil such as Shanghai and Suzhou, a new type of inert slurry with single liquid used in shield tunnel of composite stratum is carried out, and the effects of mixing time and mixing mode on the slurry performance are also discussed in this paper. Based on the analysis of the stress condition of the slurry, the shrinkage and deformation mechanism of the slurry is developed, and the shrinkage and deformation law of a new type of inert slurry under grouting pressure is studied. The main research contents are as follows: (1) by using the new formula of single liquid inert slurry used in shield tunnel of composite stratum for reference from soft soil such as Suzhou, Shanghai, and adopting the design method of uniform test, the proportioning of synchronous grouting material is optimized. It provides a scientific basis for the adoption of suitable slurry ratio in engineering. The effects of each component of the slurry on some construction properties of the slurry are discussed by multivariate nonlinear regression. (2) on the basis of the study of the variation law of the performance of the slurry with the composition of the slurry, The new inert slurry was optimized by MATLAB SQP method on the premise of meeting the strength requirement of R281.OMpa. The results are as follows: 120g of slaked lime, 574.4 g of fly ash, 203.4 g of bentonite, 1015.3 g of sand, 684.7 g of water. (3) the effects of mixing time, stirring speed and type of mixing rod on the properties of slurry were studied on the basis of optimizing the proportion of water reducer. Compared with the low speed (200r/min) stirring state, the consistency of the slurry increased by about 10%, the bleeding rate decreased by 30% and the compressive strength decreased by 10% at 28 days. (4) an experimental device for the shrinkage and deformation of the slurry was developed. The deformation law of slurry after slurry injection into shield cavities is studied systematically, and the effects of different slurry types, different grouting pressures and different strata foundation on slurry deformation are discussed. The volume shrinkage of the slurry increases with the increase of time, and the increase of volume shrinkage of the slurry decreases exponentially under the same grouting pressure. Compared with clay, the volume shrinkage and deformation rate of slurry in sandy soil is faster and the final deformation is larger.
【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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