天津滨海吹填泥浆的自重沉降固结特性研究  

Self-weight sedimentation and consolidation characteristics of hydraulic-dredged slurry in Tianjin Binhai District

作　　者：张先伟[1,2] 杨爱武[1,3] 孔令伟[2] 周奇[2] 王韬[1,3] 

机构地区：[1]天津市软土特性与工程环境重点实验室,天津300381 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [3]天津城建大学土木工程系,天津300381

出　　处：《岩土工程学报》2016年第5期769-776,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(41102200;41372291);天津市软土特性与工程环境重点实验室开放课题(2012SCEEKL006);天津市科技计划项目(15JCZDJC40600;15ZCZDSF00220)

摘　　要：以天津滨海新区吹填泥浆为研究对象,对初始含水率w_0=200%~2000%的泥浆开展长达100 d的自然沉降模型试验,研究吹填泥浆的自重沉降固结规律与形成土的微观结构特性,据此提出吹填工程设计的控制指标,为吹填工程的设计与施工提供可靠的技术支撑。结果表明,天津吹填泥浆的沉降类型主要是沉积沉降和固结沉降,沉积沉降过程分为絮凝阶段、阻碍沉降阶段、自重固结阶段。含水率临界值(或土的形成含水率)w_0*=400%,且w_0*与液限w_L具有较好的线性关系。初始含水率w_0≤w_0*,发生固结沉降,沉降量可以用一维固结理论计算;w_0>w_0*,发生沉积沉降,沉降量可以用沉积规律计算。土的形成孔隙比e_0*=10.92;沉降稳定时间Tc可用Tc=159(w_0/w_L)^(-1)计算;稳定孔隙比e_c可由分段公式计算,e_c=0.08+5.4(e_0≥13.65),e_c=0.4+1.03(e_0<13.65);絮凝屈服应力P_s=0.3 k Pa,界限孔隙比e_s=6.4。研究还表明,泥浆沉降过程其实是絮凝屈服应力与有效应力相互影响的过程,进而产生不同的沉降特征;吹填形成土在平行于沉降方向为絮凝结构,而垂直沉降方向呈堆叠结构。The model tests on hydraulic-dredged slurry with initial moisture content w_0 of 200%～2000% in Tianjin Binhai District after sedimentation of 100 days are performed to investigate the self-weight sedimentation and consolidation characteristics. The relevant indices for the hydraulic fill are suggested so as to provide reliable theoretical support for dredger filling proje_cts at the design and construction stages. The results show that the settling of the hydraulic-dredged slurry in Tianjin includes two types, deposition settling and consolidation settling, respe_ctively. The former undergoes flocculation, hindering settling and consolidation. The critical moisture content w_0＊ is 400%, and there is a linear relationship between w_0＊ and the liquid limit. When w_0≤w_0＊, the consolidation settling occurs, and the settlement can be calculated by using the one-dimensional consolidation theory. When w_0w_0＊, the deposition settling occurs, and the settlement can be calculated by using the sedimentation rule. The void ratio of soil formation e_0＊ is 10.92. The time of sedimentation stability can be calculated using Tc=159（w_0/ w_L）^（-1）. The void ratio of sedimentation stability can be calculated by the pie_cewise formulae e_c=0.08＋5.4（e_0≥13.65）and e_c=0.4＋1.03（e_013.65）. The flocculation yield stress P_s is 0.3 k Pa and the boundary void ratio e_s is 6.4. The self-weight sedimentation and consolidation is the process that the flocculation yield stress and the effe_ctive stress influence each other, so that different settlement characteristics are aroused. The micro-structure of dredged mud in parallel dire_ction to sedimentation is flocculation structure, and that in vertical dire_ction to sedimentation is a stacked one.

关 键 词：吹填泥浆 自重沉降固结 孔隙比 含水率 时间 

分 类 号：TU43[建筑科学—岩土工程]