【作者】 温永钦；

【导师】 申向东；

【作者基本信息】 内蒙古农业大学 ， 农业水土工程， 2011， 博士

【摘要】 水泥土及水泥土桩体被广泛应用于工程实践中,尤其是在软土地基处理、基坑维护、边坡加固、注浆堵水等工程中起到了非常重要的作用,由于水泥土的广泛应用,水泥土外加剂也广泛应用于水泥土中,以适应工程实际中早强、增强、增加抗渗能力等的需要,达到改善水泥土工程特性的目的,然而由于受到土质的地域性差异,掺有外加剂的水泥土工程特性也有很大差别,在工程实践中往往会出现成桩困难、强度不够等问题,使得处理成本大大增加。为此,本文针对内蒙古西部地区特定土质并充分利用当地富集的自然资源,开发研制一种新型建筑材料---天然浮石粉水泥复合土,同时通过室内试验研究了浮石粉水泥复合土的力学特性,分析了其力学性能的演化规律并在此基础上建立了相应的本构模型,这对于水泥土在内蒙古地区的广泛应用有着重要的理论意义和工程实际意义。本文首先对水泥土进行了不同水泥掺量、土料不同原始含水量、不同养护龄期的无侧限抗压强度试验,通过对试验结果分析,找出影响普通水泥土强度的主要因素,试验结果表明:随着水泥掺量的增加水泥土强度呈线性增大。随着土料原始含水量的增加水泥土强度先增大后减小,呈现抛物线型变化。随着养护龄期的增加,水泥土强度增大,两者呈较好的线性关系。通过不同浮石粉掺量、不同水泥掺量、土料不同原始含水量、不同养护龄期下的无侧限抗压强度试验和普通三轴试验,测出不同掺量下的强度值和相应的强度指标。结果表明:水泥掺量16%,浮石粉掺量8%时,在各个养护龄期下试样强度都是最大,并在此基础上确定了本文新型建筑材料的最佳配比。其次,以试验实测的大量试验数据为基础,建立了综合考虑多种因素作用下的适合内蒙古地区土质的普通水泥土和浮石粉水泥复合土的强度预测模型,分别分析了普通水泥土和浮石粉水泥土在单轴状态和三轴状态下的变形特性,并推导了普通水泥土和浮石粉水泥土的应力---应变本构方程。最后,本文结合浮石粉水泥复合土的无侧限抗压试验,采用SEM(扫描电镜)测试手段,利用土的微观结构分析方法对浮石粉水泥复合土的微结构特征进行了分析,在此基础上对浮石粉水泥复合土的固化机理和损伤特性进行了研究,初步得出了浮石粉水泥复合土的损伤演化规律,从本质上研究了浮石粉水泥复合土的强度形成及损伤演化机理。更多还原

【Abstract】 Cement and the composite pile-soil are widely applied in engineering practice, particularly in the projects including soft soil foundation treatment, maintenance of foundation pit, slope reinforcement, and preventing water by grouting. Due to the extensive application of cement, cement additives that are able to strengthen early, to enhance and to reinforce anti-permeation in practice are also in wide use in cement to improve the engineering characteristics of cement. But influenced by the regional differences of soil, the engineering characteristics of cement with additives vary differently. Thus it will lead to the problems of piling difficulty , less solidarity ,and great increase of the handling cost,Therefore, based on the local natural resources --- natural pumice in the western district of Inner Mongolia, a new type of building material --- natural pumice powder cement-soil is developed in this paper. This thesis also does research on the mechanical characteristics of cement through laboratory work , analyses the evolution of the mechanical properties and establishes relevant constitutive model, which has practical significance in both theory and engineering in the process of wide application of cement in Inner Mongolia. Firstly ,we did the unconfined compressive strengh test of cement soil by different proportions of cement,different soil raw moisture content and different curing time respectively.Through the analysis of the experimental results,we can discover the main facts which can affect the strengh of cement.The experimental results obtained from the laboratory tests show that along with the proportion of cement increasing,the strengh of cement soil also appears a linear increase.In the pace with the soil raw moisture content increasing,the strengh of cement appears a reduction after the increase,just as a parabolic change.Along with the increase of the curing time and the strengh of cement soil,the both parties appeared a quite good linear relationship.According to the different proportions of pumice powder,cement,soil raw moisture content, the unconfined compressive strengh test by different curing times and the common triaxial test,we can get the corresponding measure and data of strengh under the different proportions.The experimental results shows:when the proportion of cement is 16%, the proportion of pumice powder is 8%, the strengh is the best in any curing time.At the same time,based on those data,we can get the most suitable proportion of the new type building material as we introduced in this paper.Secondly, this paper established strength prediction model under the action of many factors taken into account, suitable for the soil in Inner Mongolia ordinary cement soil and pumice cement composite soil , based on a large number of pilot test data collection. It also analysed the deformation characteristics of the ordinary cement and pumice cement soil in uniaxial and triaxial state respectively, deducing the stress of ordinary cement soil and pumice cement soil—strain constitutive equation.Lastly, this paper analyzed the microstructural features of pumice composite cement soil, combined with analysis of soil microstructure and unconfined compression test of the pumice cement composite soil, using SEM test. It also studied curing mechanism and loss characteristics of pumice cement composite soil, and preliminarily obtained damage prediction model of pumice cement composites soil. It essentially studied the strength formation mechanism of pumice cement composite soil.更多还原