盾构废弃黏土泥浆真空脱水试验与理论研究

Experimental and Theoretical Study on Vacuum Dewatering of Waste Shield Clay Slurry

摘要:

针对泥浆池中盾构废弃泥浆在上部真空脱水作用下倒渣及运渣受限等问题，提出了一种废弃泥浆底部真空脱水方法。采用自行研制的废弃泥浆底部真空脱水装置开展了自重、自重+底部真空荷载、自重稳定+底部真空荷载、自重稳定+底部分级真空荷载4组不同脱水荷载工况下废弃黏土泥浆模型试验，分析了废弃黏土泥浆的泥?水界面沉降量、孔隙水压力以及脱水后含水率和总脱水量等物理量的变化规律。结果表明，先对废弃泥浆进行自重脱水处理，再对其底部分级施加真空作用的脱水方式具有更好的脱水效果。采用该方法对初始含水率为103.00%的废弃黏土泥浆进行脱水处理后，含水率分布范围为37.10%~62.65%，其内部孔隙水压力的最小值可达-73.09 kPa，接近底部真空作用值-80.00 kPa；且该工况相较于其余3种工况，平均沉降量分别提高了106.40%、2.91%、6.15%，总脱水量分别提高了122.0%、8.0%、5.1%。同时，基于分段线性化有限差分（CS2）模型建立了废弃黏土泥浆真空脱水数值计算模型，对废弃黏土泥浆在脱水过程中泥?水界面沉降量进行数值模拟，验证了数值计算模型的有效性。

Abstract:

To address issues such as slag dumping and limited slag transportation under the action of upper vacuum dewatering， a dewatering method of applying a vacuum load at the bottom of the waste slurry is proposed. A series of model tests were conducted on waste clay slurry under four different dewatering loading conditions by using a self-developed dewatering device that can apply a vacuum load at the bottom of the waste slurry. The rule of physical quantities such as settlement at the interface between slurry and water， pore water pressure， water content， and the total amount of water discharged after dewatering are analyzed. The results show that the fourth dewatering loading method has the best dewatering performance. After the fourth dewatering loading method was used to dewater the waste clay slurry with an initial water content of 103.00%， the water content distribution range was 37.10%?62.65%， and the minimum internal pore water pressure was -73.09 kPa， which was close to the vacuum value of -80.00 kPa applied at the bottom. In addition， compared with the other three dewatering loading methods， the average settlement was increased by 106.40%， 2.91%， and 6.15%， respectively， and the total amount of dewatered water increased by 122.0%， 8.0%， and 5.1%， respectively. Meanwhile， a numerical calculation model for vacuum dewatering of waste clay slurry is provided based on piecewise-linear finite difference CS2 model. The sedimentation at the slurry-water interface during the dewatering process of waste clay slurry was numerically simulated， and the effectiveness of the numerical calculation model was verified.