Applied Mechanics and Materials Vols. 353-356

Abstract: Based on fundamental principle of saturated/unsaturated flow and characteristic of FLAC^3Ds showing pore pressure nephogram, this paper was aimed at obtaining steady seepage within the dam, capturing the face on which pore pressure was equal to zero, and then identified the phreatic line of the dam. Using this method, phreatic line of a tailing dam in a mine was computed. The results were compared to field data. It was indicated that, the phreatic line calculated by this method was slightly higher in the mass, but was lower near the surface of the dam. This method has the merit of being faster and simpler to obtain approximate phreatic line of dams in comparison with site exploration.

Abstract: Marine sedimentary soft soil is larger water content, higher compressibility, and lower strength and buried deep. The sluice project in the marine soft soil foundation construction is beneficial to the people's livelihood needs to conduct foundation treatment. Through the scheme comparison, the sluice wing wall is located in the Yellow River estuary uses reinforced concrete pile to treat foundation. The pile diameter is 0.5m, the pile length is 19m, and the pile end is located in the sand to meet the requirements of various conditions.

Abstract: The ideal point method is a kind of multiple-goal decision analysis method, the basic idea is to construct the ideal and anti-ideal solution of multi attribute problem, with degree that near ideal solution and away from the anti-ideal solution as the basis to judge each evaluation object. Based on the basic principle of ideal point method, and comprehensive consideration of the actual geological conditions of Qingdao metro, we selected rock compressive strength, integrity coefficient, structure surface behavior, groundwater and softening coefficient as the evaluation factors of surrounding rock stability, and used the rough set theory to determine the index weight. At last, established the evaluate model for the surrounding rock stability of metro based on the rough set efficacy coefficient method. The research show that the stability analysis results are consistent with the actual excavation, so using rough set efficacy coefficient method to analysis surrounding rock stability of Qingdao Metro is feasible, which provides a new idea for the stability analysis of surrounding rock.

Abstract: In this paper, based on an actual pit excavation project, the mechanical process of excavating and retaining is simulated. Combined with the monitoring data, the stress, displacement of soil and internal force of retaining structures are analyzed, and the characteristics of deformation and force are summarized. This research offers references for safe and economical design and construction, and helps to improve the design theory of foundation pit support.

Abstract: The advantage and shortage are analyzed for the conventional calculation of stability coefficient of landslides, the four new calculating methods of safety factor of landslides are proposed. The stability coefficient of the comprehensive sliding resistance force and the maximum main stress are fit for describing the landslide state, the stability factor of each sliding block of landslide is useful for the tracting landslides. The new joint constitutive model and calculating methods of landslide are useful for describing the landslide state.

Abstract: A series of soil-structure shear tests was taken by self-made large single shear apparatus and the main factors affecting behavior of the interface are studied. It was shown that the deformation and mechanical properties are determined by the roughness of structural surface, particle size distribution and normal stress. The interface deformation includes the shear deformation of the soil near the structure due to the constraint of structural surface and the slipping deformation of soil-structure interface, they happen at the same time and interact each other . The thickness of the interface element is 4 to 5 times of the average particle diameter away from the structure surface.

Abstract: In order to forecast the stability of deep roadway and optimize the parameters of bolts, the complex stress environment and the multivariate surrounding rocks characteristics of deep roadway were analyzed. Then the classification prediction method and the numerical simulation method were simultaneously used to analysis the stability of surrounding rocks. Furthermore, the supporting parameters of bolts were also designed optimally. It was shown that the characteristics of stress distribution, deformation and failure zone of surrounding rocks are not ideal. So it is necessary to optimize the supporting parameters of deep roadway. All these research findings will provide the theory basis for bolts of deep roadway and will ensure the optimization of bolts and the stability of deep roadway in the long run.

Abstract: This paper aims at the test methods of the suction between grains of lateritic soil which is widely distributed in southern China, and proposes the test methods and principles according to the variation of the suctions various components. This paper works over the relationship between the suction and the degree of saturation through tests, and also analyzes pore fluid chemistry influence on the suction between grains. The test results show that the test principles and methods are feasible. They also show that the quantitative relationship between the unsaturated soil’s shear strength and saturation (water content), and a new understanding of the physical meaning in unsaturated condition of X, which is a empirical parameter in the principle of Bishop‘s effective stress.

Abstract: Based on J. V. Boussinesq's solution, the additional stress in the foundation is calculated under the trapezoid-distributed line load, and with the help of the line load, a formula is derived for calculating the additional stress in the foundation under the center line of trapezoid-distribution load along the Y-axis. By means of the formula, the different calculation formulas of the additional stress are determined under the load of rectangular, triangular and semi-infinite long stripe along with the change of the initial conditions. The formula can be applied to the additional stress's calculation of space problem more widely and is better than that seems to be dispersed in the reference books. Therefore, the calculation result has practical significance.

Abstract: The effective reinforcement depth is one of the most important parameters of dynamic compaction method design and construction, so far it is still lack of in-depth theoretical study. In this paper, combined with the field test, FLAC3D was used to do the numerical simulation of dynamic compaction reinforcement to cohesionless soil. By the simulation, this paper analyzed the factors which may influence the effective reinforcement depth, such as the hammers weight, drop distance, base area, and the soil parameters. The orthogonal design method was used to analyze the soil parameters sensitivity to the effective reinforcement depth. Combined with the results of numerical analysis and the traditional empirical formulae, the effective reinforcement depth calculation formula was established for cohesionless soil. Engineering verification shows that, the results estimated by the formula is reliable, and can provide certain reference for the future engineering.