近海富水软弱地层顶管施工触变泥浆配比优化及减阻性能研究

Optimization of thixotropic mud ratio and friction reduction performance for pipe jacking in offshore water-rich soft strata

摘要

触变泥浆在顶管施工中起着至关重要的作用，其良好的触变性不仅能够支撑地层，还能在顶进过程中提供润滑减阻效果，泥浆的物理性能和减阻特性直接关系到施工的效率和安全性。基于富水软弱地层的特殊需求，提出了一种新型触变泥浆配比，以膨润土、纯碱、羧甲基纤维素钠(CMC)和减水剂为原材料，进行了不同材料配比下的物理性能测试，分析了减水剂和其他成分对泥浆黏度、失水量和析水率影响。通过缩尺模型试验，进一步探讨了新型触变泥浆的减阻特性，并结合地层特性进行了参数归一化分析，优选出综合性能最优的触变泥浆配比。研究表明：减水剂能够调节泥浆水灰比，促进凝胶结构的形成，从而提高黏度、减少失水量并有效抑制析水现象。与未注浆状态下的顶进相比，采用新型触变泥浆可将摩擦系数最大降低77.1%;与不含减水剂的传统泥浆相比，摩擦系数降低38.5%,减阻效果显著。富水软弱地层顶管施工要求触变泥浆具备良好的渗透性控制能力和长期稳定性，据此遴选出10%膨润土、0.1%CMC、0.2%纯碱和0.5%减水剂的配比为最优。研究成果为解决富水软弱地层顶管施工中注浆效果差的问题提供了有效的技术支持，具有重要的应用价值。

Abstract

Thixotropic mud plays a vital role in pipe jacking construction, where its excellent thixotropic properties not only provide stratum support but also offer lubrication and friction reduction during pipe advancement. The physical properties and friction reduction performance of the mud are directly related to the efficiency and safety of the construction process. Considering the specific requirements of water-rich soft strata, a new thixotropic mud formulation was proposed using bentonite, soda ash, carboxymethyl cellulose(CMC), and a water-reducing agent. Physical property tests were conducted under different mud ratios to analyze the effects of the water-reducing agent and other components on the mud's viscosity, water loss, and water separation rate. A scaled model test was further conducted to investigate the friction reduction performance of the new thixotropic mud, and parameter normalization analysis was carried out based on stratum characteristics to identify the optimal mud formulation. The result show that the water-reducing agent can adjust the water-cement ratio and promote gel structure formation, thereby increasing viscosity, reducing water loss, and effectively inhibiting water separation. Compared with un-grouted pipe jacking, the new thixotropic mud reduced the friction coefficient by up to 77.1%, and by 38.5% compared to traditional mud without the water-reducing agent, demonstrating significant friction reduction. Pipe jacking in water-rich soft strata requires thixotropic mud with good permeability control and long-term stability. Therefore, the optimal formulation of 10% bentonite, 0.1% CMC, 0.2% soda ash, and 0.5% water-reducing agent was selected. The findings provide effective technical support for addressing poor grouting performance in pipe jacking construction in water-rich soft strata and offer significant application value.

关键词

富水软弱地层 / 顶管施工 / 触变泥浆 / 物理性能 / 减阻特性 / 泥浆配比优化

Key words

water-rich soft strata / pipe jacking construction / thixotropic mud / physical properties / friction reduction performance / mud mix optimization

Author summay

毛宇飞 (1981-), 男, 高级工程师, 硕士, 主要从事市政工程、铁路工程领域的研究。E-mail: [e-mail]

基金资助

中电建铁路建设投资集团有限公司科技项目(QDDT-YBXM-2024-02)