A Study Of Optimization Of The Ecological Building Material System Of Traditional Rammed Earth Dwellings

It is of great significance for the basic study and its development of traditional living buildings to reexamine the ecological building concept, technology and experience of earth buildings in dealing with the relationship between human beings and nature, resources as well as energy sources, and meanwhile to pursue technical ways to improve the indoor environment in earth buildings and to enhance the quality of earth buildings.As for the form of buildings, earth buildings fall into three subcategories: cave buildings, adobe buildings, and rammed earth buildings, among which rammed earth buildings has been constructed widely in the western rural area of China (in the provinces of Shaanxi, Yunan, Xinjiang, Gansu, Ningxia and Qinghai).The thesis makes a systematic study of the mechanical character, durability and modification of rammed earth materials used in rammed earth buildings on the basis of analysis of the fixture system of rammed earth buildings and consideration of the architectural characteristics in different regions.The thesis puts forward the designing concept of semi-rigid plan for the first time through analysis of stress-bearing character of rammed earth buildings and points out two ways for the design of puddle wall structure with reference to some other norms and in consideration of the floor height as well as the quality of rammed earth materials. Furthermore, the formula for calculating the stress-resisting bearing power of the rammed earth load-bearing wall and relevant key parameters are also presented in the thesis.The thesis carries out a large amount of testing on the compression strength of rammed earth materials on the basis of a comprehensive analysis of the internal and external factors that may influence the character of rammed earth wall materials and the testing of the soil property in different regions in China. Under the condition thatunmodified rammed earth materials can hardly meet the demand of load-bearing rammed earth elements, the thesis carries out a comprehensive testing on the modification of tamping materials, including single addition, mixed addition and comparison of optimization, and the corresponding rational amounts for modified varieties of tamping materials to present their best properties are achieved. The testing proves that mixed addition optimizing modifying technology is an effective way to enhance the compression strength of rammed earth materials. The thesis also advances the formula for estimating the compression strength of rammed earth wall materials for the first time drawing on the means of fuzzy mathematics, which provides a foundation for controlling and evaluating the quality of load-bearing wall materials in rammed earth buildings.The equivalent loading and modification distribution curve of tamping and modified tamping materials is indicated in the thesis on the basis of previous studies relevant to consititutive relation theory and numerous testing data. In addition, the one waycompression stress-strain model is established in the thesis drawing on certain computer software.The thesis analyzes stress variations of rammed earth materials in their elastic scope through repetitive loading and unloading testing and puts forward the scopes of the elasticity modulus of bearing tamping materials in a quantified way for the first time, which provides a basis for the calculation of the rigidity of rammed earth wall elements.The shear and detrusion of rammed earth materials with various compositions and the maximum shear-resisting strength indices before and after the modification of rammed earth materials are achieved in the thesis on the basis of testing the shearing strength of rammed earth materials before and after hardening. The thesis also proves the rationality of taking the shear-resisting intensity of rammed earth materials after hardening as the scope of aseismic design in rammed earth buildings. Furthermore, the feasible approach to enhancing the shear-resisting strength of rammed earth materials by adding coarse stone materials with rammed earth mate...