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盾构穿越松散地层时,需事先采用开挖(钻孔)回填、压力注浆、旋喷加固等方式对地层进行预处理,以保证盾构施工安全。针对盾构掘进的要求,基于传统袖阀管注浆工艺可控的特点,结合研制的2种可控浆液(可控填料和可控水泥膏状浆液),提出一种具有操作性强、提管便利、加固范围可控以及加固体强度适宜等优点的双控注浆新方法。依据双控注浆新方法的工作原理,重点推导了可控浆液扩散方程及可控填料封孔止浆可控表达式,并定量分析可控浆液的扩散和止浆能力,最后将研究成果成功应用于越江盾构隧道松散地层注浆工程。研究成果表明:提出的可控注浆方法可行,注浆后地层连续性和整体性得到了显著提高,加固区域内检查孔取芯过程钻进平稳,回水正常,芯样完整,加固体28 d抗压强度与渗透系数均达到设计标准;理论推导虽与现场实测值存在一定误差,但能满足工程要求;结合理论推导和现场试验结果,为达到最佳注浆效果,单次注入可控填料封孔高度应综合考虑孔深与分段次数,且不宜大于15 m,径向扩散距离应小于孔排距的25%,可控填料塑性强度宜控制在0.3~0.5 MPa。
Shield through the loose strata, the need to use the excavation (drilling) backfill, pressure grouting, rotary jet grouting and other pre-treatment of strata in order to ensure the safety shield construction. According to the requirements of shield tunneling, based on the controllable characteristics of the traditional sleeve valve grouting process, combined with two kinds of controllable slurry (controllable filler and controllable cement paste slurry) developed, this paper proposed a method with strong operability, Tube convenience, reinforcement of the controllable range of strength and strength of the solidification of the double-controlled grouting a new method. According to the working principle of the new method of double grouting, the controllable grout diffusion equation and the controlled expression of pluggable grouting are mainly deduced, and the diffusion and grouting ability of controlled grouts are quantitatively analyzed. At last, the successful research results It is used in the loose stratum grouting project of the shield tunnel in Yuejiang River. The research results show that the proposed controllable grouting method is feasible, the continuity and integrity of the formation after grouting have been significantly improved, the check hole coring process in the reinforcement area has a smooth drilling, normal backwater, complete core sample, d compressive strength and permeability coefficient have reached the design standards; theoretical derivation although there is some error with the field measurements, but can meet the engineering requirements; combined with theoretical derivation and field test results, in order to achieve the best grouting effect, a single injection control The height of plugging holes should be considered in combination with the hole depth and the number of sub-sections, and should not be larger than 15 m. The radial diffusion distance should be less than 25% of the hole row spacing. The plastic strength of controllable packing should be controlled at 0.3-0.5 MPa.