Applied Mechanics and Materials Vols. 256-259

Abstract: When a new building or a heaped load is near to a existing building, the neighboring loads will cause the existing building foundations unevenly settle, tilt or even crack which will affect both the safety and normal use of the buildings. Therefore, it is necessary to strengthen the relate research in this area. In this paper, based on the Flemish theory the additional stress of the building foundation was deduced, and the soil settlement formula was calculated by the splitting summation method. The engineering example showed the influence of the neighboring loads on the existing building foundations.

Abstract: The fully mechanized top-coal caving System is a large scale complex system. The conception of system and its basic problems, such as structure, function, inner-outer environment, boundary, parameter and so on, are defined in this paper. Through the thorough research, the basic theory of fully mechanized top-coal caving will be consummated, the stability and reliability of the system will be worked over by systems engineering, and the complex problems of equipment-selection and surround rock-displace which involved of many factors will be resolved.

Abstract: Based on the microscopic damage mechanics, the finite element method is applied to investigate theinfluence of the inclined joint on the rock fragmentation under impact loading.The viscous boundary is considered to elimilate the influence of the reflected stress waves from the boundary. The result shows the inlcined joints change the direction of crack propagation. The lateral cracks appeare first, and thenthe main cracks tend to propagate to theleft side.

Abstract: In this article, we analyse several types of composite foundation load test result, then expound that when we design composite foundations, we should choose reasonable kind of composite foundations according to accurate engineering geology and hydrogeology conditions and characteristic of buildings , otherwise will not reach the expected effect.

Abstract: More detailed information about the bearing capacity and integrity of the pile can be obtained by high strain dynamic test than by dead-load test [1]. Engineering examples show that the bearing capacity of the prestressed pipe pile gradually increase with the growth of the resting time, and the ultimate bearing capacity of the pile can reach up to 2 times more than the initial bearing capacity. Through the study of the time effect mechanism, it is found that the increment of ultimate bearing capacity of the single pile is mainly caused by side soil resistance. The end resistance has little influence on the time effect of bearing capacity of pile.

Abstract: This paper is used to study on analysis and prediction of surface subsidence caused by pipe roof reinforcement method construction. Take one of the Shenyang's sewage disposal projects to be investigated, it monitored on field surface subsidence in construction of underdrain. During the measurement and monitoring, except for conventional measurement of surface subsidence according to code and peripheral convergence and so on, in order to analysis changes of stress and strain of the pipe roof in whole construction of underdrain. it respectively arranges JMZX-212 intelligent string type of strain gauge in both internal and external sides of vault and hance. It used the Element Birth/Death of finite element software basing on field data, using elastic-plastic and nonlinear finite element method. Material constitutive relationship used mohr-coulomb model, simulating process of tunnel of excavation and support, researching and stimulating surface subsidence. Value of surface settlement was calculated via numerical simulation in applying finite element theory, it based on prototype of engineering, which was in accord with measurement value in field. The correctness of soil constitutive model chosen and boundary conditions used is verified, meanwhile, numerical simulation shows validity of method.

Abstract: According to the distribution law of the abutment pressure before and behind the working face, the calculation model of the coal floor stress was established and the distribution law of the floor stress along with the advance of face was analyzed. The results show that, in working face ahead, the vertical stress and horizontal stress have generally increased, and the vertical stress is more than horizontal stress, and floor rock strata is in compression bending state with mining influence. Then in the rear of working face, the vertical stress and horizontal stress have generally reduced to less than the original rock stress, and horizontal stress is more than vertical stress. Thus rock bottom is in reverse curving condition, and upward migration of the strata causes the floor drum. Such results can provide theoretical basis for water inrush with pressure mining and treatment of the floor drum of the working face.

Abstract: Considering the seepage stress coupling of fractured rock mass, the multiple holes grouting problems were simulated to analyse the spread regularity by Universal Distinct Element Code(UDEC).The results show that the correlation between grouting pressure and the diffusion distance is positive, whereas the correlation between ground stress and diffusion distance is negative; With the raising of grouting holes, the diffusion distance is increasing and becoming more uniform in all directions, and the grout pressure and saturation is falling and attenuation amplitude is decreasing along the direction of grout diffusion; With the increasing of fracture aperture, the grout diffusion distance is increasing, and the grout pressure and saturation attenuation amplitude is decreasing along the direction of grout diffusion.

Abstract: The characteristics and distribution rule of viscous soil in unsaturated zone is the key factor that influence on the natural attenuation of pollutant, so, it is necessary to study the antifouling performance of cohesive soils. In this paper, the barrier adsorption effect of COD (Chemical Oxygen Demand) and TDS (Total Dissolved Solids) were discussed according to soil column experiment. Meanwhile, it analyzed the impact of some properties of viscous soil on experimental result, such as initial PH, initial moisture content, initial organic matter and microorganism content. Research results are shown as follows. Firstly, initial moisture content is passively correlated with the adsorption of TDS. Secondly, organic matter content is positively correlated with the adsorption of COD. Thirdly, microorganism content is positively correlated with the adsorption of COD and TDS. The Antifouling ability of soil may be evaluated by means of filtration capability and adequacy thickness. Research results would provide basis for pollution control of soil.

Abstract: Lime treatment technique is a convenient and common method used to improve expansive clays in engineering properties. The soil-water characteristic curve (SWCC) plays a role on engineering features of unsaturated lime-treated expansive clays. Herein, the soil-water characteristic tests by means of GDS and simulations were conducted to investigate the SWCCs of lime-treated expansive clays in Hefei. The results show that lime-treated expansive soil behaves hysteretic characteristics. Under the same value of suction, the higher cell pressure the larger the volumetric water content is. The numerical simulations from Fredlund model do good agreement with tests.