含盐地层顶管润滑泥浆抗盐及抗渗性能试验研究

为解决高含盐地层盐侵顶管润滑泥浆造成滤失量过大、黏度下降、动塑比下降，导致管周摩阻力增大，影响顶管施工的问题，依托山东省黄水东调二期工程的地质勘察结果，选用凹凸棒土、HV-CMC等抗盐材料，通过配浆试验得到配浆水+5%加量凹凸棒土+5%加量膨润土+0.35%加量NaOH+0.8%加量HV-CMC的泥浆配方。采用抗盐试验和抗渗试验测试盐侵前后黏度、滤失量、抗渗性等指标，得到结论如下： 1）钙镁离子由于价位高、水化能力差，盐侵影响大于钠离子； 2）润滑泥浆的黏度随盐侵增大而表现出先迅速减小后趋于稳定的现象； 3）地层粒径对泥浆抗渗性影响很大，建议泥浆使用前增设原状土中的抗渗性测试。

Salt Resistance and Impermeability of Pipe Jacking Lubricating Slurry in Salt Formation

Salt invasion causes substantial filter loss, viscosity and dynamic plastic ratio reduction of the lubricating slurry used for pipe jacking, and increases the pipe friction resistance affecting the pipe jacking construction. Hence, a case study is conducted on the geological survey results of the 2nd phase of the Yellow river to East China water diversion project in the Shandong province. Salt resistant materials, such as attapulgite and HV-CMC are selected, and a slurry formula of water +5% attapulgite +5% bentonite +0.35% NaOH + 0.8% HV-CMC is obtained using a slurry test. Salt resistance and permeability experiments are conducted to test the viscosity, filter loss, and impermeability indexes before and after salt invasion. The following is concluded based on the results: (1) Owing to the high valency and poor hydration capacity, calcium and magnesium ions have a greater influence on salt invasion than sodium ions. (2) The viscosity of the lubricating slurry first rapidly decreases and then tends to be stable with an increase in salt intrusion. (3) The formation particle size has a great influence on the impermeability of slurry. The results suggest that the impermeability of undisturbed soil should be tested before slurry application.