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Zhang P.,Sun Yat Sen University | Zhang P.,Guangzhou Urban Planning Survey and Design Institute | Tang L.,Sun Yat Sen University | Jiang L.,Sun Yat Sen University | Deng Z.,Sun Yat Sen University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

Referring to the concept of coordination number in crystallography and mineralogical science and powder material science and engineering, based on the formulas of Smith, Fisher and Young-Laplace, the corresponding relationship between macro variables such as water content, dry density, void ratio and micro variables such as saturation angle, volume between two soil particles, the quantitative calculation formula of matric suction is deduced. Calculation results show that: (1) Matric suction of unsaturated soil decreases with the increasing water content nonlinearly. (2) There is a linear correlation between matric suction and dry density, as well as void ratio. Matric suction increases with the increasing dry density at low water content while keeps no changes at high water content. The calculation result matches existing experimental results.

Zhang P.-C.,Sun Yat Sen University | Zhang P.-C.,Guangzhou Urban Planning Survey and Design Institute | Tang L.-S.,Sun Yat Sen University | Deng Z.-W.,Sun Yat Sen University | Jiang L.-Q.,Sun Yat Sen University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

Based on the example of cubic loose accumulation, a quantitative relation expression is deduced theoretically between wet suction and water content of unsaturated soils. The suction tests on remodeling fine grain sand soil with different water content are carried out, and a curve-fitting of the test results is analyzed. Theoretical calculations and experimental results show that for specific unsaturated soils, with the increase of the water content, the suction wet increases first and then decreases, which is the same as that when there is a certain boundary of water content. This agrees with the fact that in a certain range, the strength of the unsaturated soils, especially the unsaturated sand soils, increases first and then decreases with the increase of the water content. It indicates that the wet suction, instead of matrix suction, is the important part of effective stress.

Tang L.-S.,Sun Yat Sen University | Tang L.-S.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resources | Sang H.-T.,Sun Yat Sen University | Sang H.-T.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resources | And 4 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2013

Unsaturated granite residual soil is mainly ferruginous cement, its strength decreases sharply in water, structural significant, showing brittle-elastoplastic damage characteristics, whose soil particle joint function is the core problem of structure and brittle-elastoplastic damage. The unsaturated soil particle joint function is discussed; it is divided into contact and non-contact joints, and these two kinds of joints are expressed as suction effects in soil particle intergranular interactions, that is the suction between grains composed of variable structure suction and wet suction. For unsaturated granite residual soil, particle joint function should be paid more attention. Unsaturated granite residual soil's contact joint is dominated by ferruginous cementation and all levels of granularity composition mixtures as sand, clay and so on; they cause the suction between grains changing greatly in water or disturbance, resulting in the properties of the brittleness in the mechanics of unsaturated granite residual soil. Then through theoretical derivation, by referencing coordination number, the Smith formula, and the Fisher formula in mineralogy, crystal powder mechanics and engineering, quantitative calculation formula of variable structure suction and the soil accumulation mode, dry density, void ratio, water/saturation are given; and the rationality of the calculation formula is verified by tests. Then we research and realize that free iron oxide cement is the fundamental point of granite residual soil's property of brittle-elastoplasticity, so a masonry model is used; and then void ratio and structure parameter are applied to construct the brittle damage process function; a theory model which can reflect the damage of unsaturated granite residual soil elastoplasticity is established. Through the comparison of calculation and experiment results. The results show that the model established above can well reflect the unique stress-strain relationship of unsaturated granite residual soil. It can explain well the mechanism of unsaturated granite residual soil which is easily destroyed in water or disturbance according to theory.

Zhao J.,Tianjin University | Zhao J.,Nanyang Institute of Technology | Guo J.,Nanyang Institute of Technology | Zhang S.,Nanyang Institute of Technology | And 2 more authors.
Information Technology Journal | Year: 2013

In order to improve the living comfort level of the low-income groups, and the belonging of the affordable housing community residents, the research group take Nanyang green community housing design as the research object, using the computer software for community planning phase of the thermal environment, wind environment, light environment for simulation analysis. The result showed the micro-climate, thermal environment, and adjusting the temperature of the district as well which is the affordable housing community worthy of promotion of green building technologies for small and medium-sized cities. It also provides the reference for the similar project planning in the process of ventilation, lighting, shading, such as green design strategy research. © 2013 Asian Network for Scientific Information.

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