砂土层大直径顶管施工顶力控制与施工稳定性研究

发布时间：2018-03-23 14:10

本文选题：顶管　切入点：触变泥浆　出处：《东北大学》2014年硕士论文

【摘要】：在顶管施工中,为了在土中顺利顶进管道,千斤顶的顶力需要克服各种阻力及外界因素的影响(纠偏、后背位移)；为了减小顶进时管节外壁的摩擦阻力,在管节与土体间注有减摩用的触变泥浆；因此,施工中的顶力控制与施工稳定性的研究将对实施顶管工程具有较大的工程价值。论文以沈阳地区砂土层大直径顶管工程为工程背景,采用数值模拟结合现场监测的手段进行研究。沈阳地区以砂砾(卵)石土层为主,顶进大直径顶管可借鉴的工程经验并不多,因此首先从数值模拟的角度,提出了初始顶力预估顶进过程中所需顶力的方法,并与实际监测结果进行了对比,然后对沈阳地区顶管顶进中的触变泥浆配合比进行了分析,比较了7种浆体的顶力曲线。并对注浆施工、纠偏施工过程中的稳定性情况进行了分析,最后基于强度折减法的计算原理得到了顶管工程施工开挖面的安全系数。研究结果表明,采用数值模拟方法进行顶管顶进过程中的顶力预估,并为中继间的合理布置提供参考是可行的；沈阳地区顶管施工优化的触变泥浆膨润土与水的质量配比为1：9,并且触变泥浆中的用水量对于减阻效果有明显影响；在顶管纠偏施工过程中管体的最大压应力随着纠偏压力的增大而增大,因此在进行纠偏施工时需要对纠偏压力进行合理的控制。为了确保沈阳地区顶管工程开挖面的安全稳定,开挖面的支撑压力20kPa以上来施加是偏于安全的。此时该工程的开挖面安全系数为1.39,开挖面偏于稳定。
[Abstract]:In pipe jacking construction, in order to push the pipe smoothly in the soil, the jacking force needs to overcome the influence of all kinds of resistance and external factors (correction, back displacement), in order to reduce the friction resistance of the outer wall of the pipe when jacking, Thixotropic mud for friction reduction is injected between pipe joints and soil; therefore, The research on the control of the jacking force and the stability of the construction will have great engineering value for the pipe jacking engineering. This paper takes the large diameter pipe jacking project of the sand layer in Shenyang area as the engineering background. Numerical simulation combined with field monitoring is used to study. In Shenyang area, sand gravel (egg) soil is the main soil layer, and there is not much engineering experience that can be used for reference when jacking pipe with large diameter. Therefore, first of all, from the point of view of numerical simulation, In this paper, the method of estimating the required force in the process of jacking with initial force is put forward, and compared with the actual monitoring results, the thixotropic mud mixture ratio in the jacking of pipe jacking in Shenyang area is analyzed. The top force curves of 7 kinds of slurry are compared, and the stability of grouting construction and rectifying construction is analyzed. Finally, based on the calculation principle of strength reduction method, the safety factor of the excavated surface of pipe jacking engineering is obtained. The research results show that the numerical simulation method is used to predict the top force in the process of jacking pipe jacking. The optimum mass ratio of thixotropic mud bentonite and water in pipe jacking in Shenyang area is 1: 9, and the water consumption in thixotropic mud has obvious influence on drag reduction effect. In order to ensure the safety and stability of excavating surface of pipe jacking engineering in Shenyang area, the maximum compressive stress of pipe body increases with the increase of rectifying pressure during pipe jacking and rectifying construction, so it is necessary to carry out reasonable control of rectifying pressure in the process of rectifying deviation construction, in order to ensure the safety and stability of the excavated surface of pipe jacking engineering in Shenyang area. The safety factor of the excavated face is 1.39, and the excavating surface is stable.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU990.3

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