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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。
In this study, the natural sedimentation model experiment of 100 years of mud with initial water content w0 = 200% ~ 2000% was carried out to study the effect of blowing and filling mud in Tianjin Binhai New Area on the self - According to the above, it puts forward the control index of the engineering design for filling and filling, and provides reliable technical support for the design and construction of the filling and filling engineering. The results show that the sedimentation types of Tianjin Blowing and Filling mud are mainly sedimentation and consolidation settlement. Sedimentation and sedimentation process is divided into flocculation stage, obstruction stage and consolidation stage. The critical value of moisture content (or the formation of moisture content of soil) w_0 * = 400%, and w_0 * and the liquid limit w_L has a good linear relationship. Initial water content w_0≤w_0 *, consolidation settlement occurs, the settlement can be calculated by one-dimensional consolidation theory; w_0> w_0 *, the occurrence of sedimentation, sedimentation can be calculated using the deposition law. The settling time Tc can be calculated by Tc = 159 (w_0 / w_L) -1. The stable void ratio e_c can be calculated by the piecewise formula, e_c = 0.08 + 5.4 (e_0≥13.65) , e_c = 0.4 + 1.03 (e_0 <13.65); flocculation yield stress P_s = 0.3 kPa, boundary void ratio e_s = 6.4. The study also shows that the mud subsidence process is actually the interaction between the yield stress and the effective stress of the flocculation process, which leads to different settlement characteristics. The fl ood-forming soil is in a flocculation structure parallel to the sedimentation direction, while the vertical sedimentation direction is in a stacked structure.