杭州海相软土的固化及其理论研究

发布时间：2018-08-17 13:50

【摘要】：杭州地区海相沉积软土具有天然含水量高,压缩性高,承载力低,有机质含量高等工程特性,在对其进行固化处理时,由于高有机质含量的存在,水泥固化效果并不理想,因此有必要选择适宜的添加剂来改善水泥固化的效果,从而配制一种高效复合固化剂,并且开发针对各种不同有机质含量软土的固化剂产品；为了将所开发的固化剂更好的应用于工程实际,需要对固化土的强度形成规律和固化土渗透性等物理力学特性进行研究；另外,研究适宜固化土的本构模型是对固化土进行数值模拟的基础。为此,本文主要开展如下工作： (1)从软土的成因分布,化学,物理力学性质,应力应变关系,结构性等方面对杭州地区第四纪全新统海相沉积软土进行系统的研究,从而科学评价杭州软土的工程特性。 (2)针对杭州地区海相软土高有机质含量和高含水量的特性,在添加水泥的基础上,从选择合适的矿物填料,减薄土壤双电层的厚度,提高土壤PH值,增强早期强度,调节水泥离子和黏土颗粒的活性等五个方面选定生石膏,生石灰,碳酸钠,FDN,水玻璃,三乙醇胺等六种添加剂来改善有机质软土的固化,开发性能优越的高效复合固化剂。 (3)利用响应面法来对添加剂进行优选和配方研究,并考察各影响因子的交互作用规律。确定不同有机质含量的最优固化剂掺量和水泥掺量,使得所开发的固化剂产品能适应于各种不同有机质含量的软土。 (4)采用水泥及固化剂GX08对有机质土进行固化,分析各种因素对强度的影响规律,在此基础上,建立同时考虑固化土中有机质含量、水泥掺量、固化剂掺量和龄期影响的固化土综合强度预测模型。 (5)分析固化土的重度和含水量等指标受不同配比和龄期影响的变化规律。在对复合固化剂作用下固化土渗透性的变化规律进行研究的基础上,建立复合固化土的渗透系数预测方法。 (6)考虑有机质含量,固化剂掺量和水泥掺量三个因素影响下的损伤本构模型参数的变化规律,以及损伤变量的演化规律,最终建立综合考虑有机质含量,固化剂掺量和水泥掺量影响的固化土弹塑性损伤模型。
[Abstract]:The marine sedimentary soft soil in Hangzhou area has the engineering characteristics of high water content, high compressibility, low bearing capacity and high organic matter content. When curing the soft soil, the solidification effect of cement is not ideal because of the existence of high organic matter content. Therefore, it is necessary to select suitable additives to improve the effect of cement curing, so as to prepare a kind of high efficiency compound curing agent, and to develop the hardener product for different organic matter content soft soil. In order to better apply the developed curing agent to the engineering practice, it is necessary to study the physical and mechanical properties of the solidified soil, such as the strength formation law and the permeability of the solidified soil. The study of constitutive model of suitable solidified soil is the basis of numerical simulation of solidified soil. For this reason, the main work of this paper is as follows: (1) A systematic study on the formation distribution, chemical, physical and mechanical properties, stress-strain relationship and structure of the Quaternary marine sedimentary soft soil of the Quaternary in Hangzhou area is carried out. Therefore, the engineering characteristics of Hangzhou soft soil are scientifically evaluated. (2) aiming at the characteristics of high organic matter content and high water content of marine soft soil in Hangzhou area, on the basis of adding cement, the suitable mineral filler is selected. Reducing the thickness of double electric layer of soil, increasing the PH value of soil, enhancing early strength, adjusting the activity of cement ion and clay particle, selecting raw gypsum, quicklime, sodium carbonate FDN, water glass, etc. Six kinds of additives, such as triethanolamine, are used to improve the solidification of organic soft soil and to develop high efficiency compound curing agent with superior performance. (3) the optimum selection and formulation of additives are studied by using response surface method. The interaction law of each influencing factor was investigated. The optimum amount of curing agent and cement content of different organic matter content are determined to make the product of curing agent suitable for soft soil with different organic matter content. (4) cement and GX08 are used to solidify organic soil. On the basis of analyzing the influence of various factors on strength, the organic matter content and cement content in solidified soil are considered simultaneously. The comprehensive strength prediction model of solidified soil affected by the content and age of curing agent. (5) the variation law of the degree and water content of solidified soil affected by different ratio and age were analyzed. On the basis of studying the changing law of permeability of solidified soil under the action of compound curing agent, the method of predicting permeability coefficient of composite solidified soil is established. (6) considering the content of organic matter, The variation of damage constitutive model parameters and the evolution of damage variables under the influence of three factors, the content of curing agent and the content of cement, are discussed. Finally, the organic matter content is considered synthetically. The elastoplastic damage model of solidified soil affected by the content of curing agent and cement.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU447

【参考文献】