张雪, 万中正, 王传银, 等. 2021. 无水砂层中矩形顶管施工用触变泥浆配比优化及减阻性能试验[J]. 工程地质学报, 29(5):1611-1620. doi: 10.13544/j.cnki.jeg.2021-0508.
    引用本文: 张雪, 万中正, 王传银, 等. 2021. 无水砂层中矩形顶管施工用触变泥浆配比优化及减阻性能试验[J]. 工程地质学报, 29(5):1611-1620. doi: 10.13544/j.cnki.jeg.2021-0508.
    Zhang Xue, Wan Zhongzheng, Wang Chuanyin, et al. 2021. Optimization thixotropic slurry ratio and drag reduction performance test for rectangular pipe jacking in anhydrous sand layer[J]. Journal of Engineering Geology, 29(5):1611-1620. doi: 10.13544/j.cnki.jeg.2021-0508.
    Citation: Zhang Xue, Wan Zhongzheng, Wang Chuanyin, et al. 2021. Optimization thixotropic slurry ratio and drag reduction performance test for rectangular pipe jacking in anhydrous sand layer[J]. Journal of Engineering Geology, 29(5):1611-1620. doi: 10.13544/j.cnki.jeg.2021-0508.

    无水砂层中矩形顶管施工用触变泥浆配比优化及减阻性能试验

    OPTIMIZATION THIXOTROPIC SLURRY RATIO AND DRAG REDUC ̄TION PERFORMANCE TEST FOR RECTANGULAR PIPE JACKING IN ANHY ̄DROUS SAND LAYER

    • 摘要: 顶管施工中,触变泥浆起到润滑减阻和支撑地层的作用,是保证顶管施工安全快速进行的重要材料,其减阻性能的优劣是影响顶管施工的重要因素。本文以北京城市副中心通州区潞城镇综合管廊工程为依托,以膨润土、羧甲基纤维素钠(CMC)和纯碱为触变泥浆原材料,进行不同材料配比的正交试验,优选出了触变泥浆的最优配比;开展缩尺的模型试验,探究了触变泥浆的减阻效果。此外,通过扫描电镜显微观察,研究了触变泥浆的微观结构和减阻机理。研究表明:触变泥浆原材料含量对泥浆的性能有很大的影响,10%膨润土、0.2% CMC、0.5%纯碱和89.3%水是泥浆原材料的最优配比,该配比下的泥浆流动性和触变性较好,失水量较小,形成的“滤饼”较为致密,综合性能最优,且该配比下的触变泥浆可以使试块和砂土之间的摩阻系数降低40%,减阻效果显著;触变泥浆呈薄片层状结构,其主要矿物成分蒙脱石具备晶格取代、阳离子交换等微观特性,使得触变泥浆宏观上表现出触变性进而发挥减阻作用,最终以泥浆套的形式充分隔离管道和周围的土体,从而实现减阻功能。

       

      Abstract: In pipe jacking construction, thixotropic mud plays the role of lubrication, drag reduction and supporting formation. The mud is an important material to ensure the safe and rapid pipe jacking construction. Its resistance reduction performance is an important factor affecting the pipe jacking construction. This paper is based on the comprehensive pipe gallery project of Lucheng Town, Tongzhou City, the vice center of Beijing City. It takes bentonite, CMC and soda as the raw materials of thixotropic slurry, carries out the orthogonal test of different material ratio, and optimizes the optimal ratio of thixotropic slurry. The drag reduction effect of thixotropic slurry is investigated by scale model test. In addition, the microstructure and drag reduction mechanism of thixotropic mud are studied by SEM. The results show that: the content of thixotropic slurry raw materials has a great influence on the performance of the mud. 10% bentonite, 0.2% CMC, 0.5% soda ash and 89.3% water are the optimal proportion of slurry raw materials. Under this ratio, the slurry has good fluidity and thixotropy, small water loss, dense "filter cake" and optimal comprehensive performance. In addition, the friction coefficient between the test block and sand can be effectively reduced by 40% with the thixotropic slurry, and the drag reduction effect is remarkable. The thixotropic slurry has a lamellar structure, and its main mineral component montmorillonite has micro characteristics such as lattice substitution and cation exchange, which makes the thixotropic slurry show thixotropy macroscopically and plays the role of drag reduction. Finally, the pipe and surrounding soil are fully isolated in the form of mud sleeve, so as to realize the drag reduction function.

       

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