Applied Mechanics and Materials Vols. 580-583

Abstract: Based on the self-design model experimental system of dynamic soil-pile dynamic interaction, strong horizontal dynamic load was exerted to two models of squeezed branch pile, and the bearing plate location of the two squeezed branch piles is different. The model experiment adopt digital frequency converter to control the loading frequency, and use spring of different stiffness coefficient to achieve different load level. In order to analyze the action of bending moment and the status of lateral earth pressure changes, different sizes of excitation frequency and excitation load were setted during the test.

Abstract: Using self―made model device, researchers studied the characteristics of foundation settlement of sandy soil and pile foundation load―bearing in sandy soil. Through weight loading, researchers analyzed the phenomenon of foundation settlement. Then, researchers embedded friction piles in sand, so as to analyzed pile foundation bearing capacity. The methods and results of the research can provide guidance for teaching of Soil mechanics and foundation engineering.

Abstract: T-shaped soil-cement deep mixing column load transfer mechanism is different from the general section column. Basing on the fast Lagrangian finite difference method, we study the load transfer mechanism of T-shaped soil-cement deep mixing column at different load levels, expanding head height and the ratio of upper and lower pile diameter. By the numerical simulation we obtained that the axial force plummeted value of expanding head flange increases with the load and the ratio of upper and lower pile diameter increasing, it will decreases when the height of expanding head increasing.This paper can provide a reference for the design of T-shaped soil-cement deep mixing column.

Abstract: In this work, one-dimensional problem has a well-known linear solution and, thus, provides a simple verification of the consolidation capability using numerical solution. The coupling is approximated by the effective stress principle, which treats the saturated soil as a continuum, assuming that the total stress at each point is the sum of an effective stress carried by the soil skeleton and a pore pressure in the fluid permeating the soil. This fluid pore pressure can change with, and the gradient of the pressure through the soil that is not balanced by the weight of fluid between the points in question will cause the fluid to flow: the flow velocity is proportional to the pressure gradient in the fluid according to Darcy's law. A typical case is a consolidation problem. Here the addition of a load to a body of soil causes pore pressure to raise initially; then, as the soil skeleton takes up the extra stress, the pore pressures decay as the soil consolidates. The Terzaghi problem is the simplest example of such a process. For illustration purposes, the problem is treated with and without finite-strain effects. The numerical solution agrees reasonably well with the analytical solution, with some loss of accuracy at later times.

Abstract: Anchoring technique has been widely used in slope engineering because of its reinforcing function to rock and soil mass. Yet the full understanding of the anchoring mechanism still lags behind the engineering practice. This paper introduces the design process and construction technology of the grouting anchor in slope reinforcement engineering. Based on bolt grouting test, it is found that the effective anchorage length of the grouting anchor depends on the size of the anchor solid and relative physical and mechanical properties of surrounding rock and soil. Research shows that the distribution of shear stress is uneven along the anchoring length. It mainly amasses within the front 1/3 part of the anchoring and increases with the development of outside load. The conclusion is helpful to describe the anchoring mechanism and instructive for engineering practice.

Abstract: According to the first-stage geologic investigation reports of the line 1 and line 2 in Ningbo rail transit, the natural density (ρ) and the vane strength (C_u) probability distribution of the typical layers in Ningbo area were studied in this paper. Besides, the reliabilities of the typical layers foundation bearing capacity in Ningbo area were evaluated by the checking point method. It is found that (1) the natural densities of the typical layers in Ningbo area show good normal distribution as their corresponding variation coefficients (δ) are small. Unfortunately, the vane strengths of the typical soils in Ningbo area show poor normal distribution as their corresponding variation coefficients (δ) are large. (2) The soil parameters variation has significant influence on the reliability index β. Moreover, β is more sensitive to the variation of ρ than to the variation of C_u. (3) As the safety coefficient methods can not consider the influence of the soil parameters variation on the foundation stability, it is suggested that the foundation stability in Ningbo area should be evaluated by the reliability analysis method.

Abstract: The process of urbanization has brought prosperity of economy and improvement of people's living standard, but larger and larger life garbage in the city could be found due to excessive concentration of population. Sanitary landfill method has been widely applied in many cities for convenience and economy. Anti-seepage treatment and anchorage technology are two key issues to reduce the pollution of leachate on surrounding environment and underground water sources with construction of modern sanitary landfill area. In this paper, the anchorage technology of high-density polyethylene (HDPE) membrane was researched on the steep slope in the valley-type sanitary landfill. The test and theory of anchorage were also studied in the northwest region. The results show that anchorage force reaches the maximum when the anchoring platform is horizontal. It keeps the geomembrane more stable if the slope angle is within 45° when the slope height is over 6m.

Abstract: High loess slopes are easily unstable because of the water sensitivity of loess, therefore, the study on stability of high loess slopes is a very important task for water and soil conservation on loess plateau. Forcus on the inefficiency of current graphic method, after considering main influencing factors of stability of high loess slopes, such as lithology, topography, groundwater conditions, slope water content and seismic intensity, etc., on the basis of graphic method, an automatic table lookup program was developed, moreover, the interfaces of graphic method were compiled based on MATLAB platform, which could automatically generate plenty of obvious characteristics of slope data for further modeling.

Abstract: Based on the engineering geological conditions of an artificial slope is analyzed using a combination of numerical simulation, the slope ratio method and other methods, the slope stability was evaluated, It has a certain reference to artificial slope stability evaluation that similar to a combination of soil and rock.

Abstract: Impact loads caused by punching pile construction of highway bridges are bound to disturb stratum surrounding the buried pipeline adjacent to, which would adversely affect the normal use and safe operation of buried pipelines. Through developing field micro-seismic trial, the characteristics of vibration attenuation and sphere of influence were analyzed, in order to assess its impact on buried pipeline nearby. It drew conclusions that the amplitude of vibration energy had been enlarged with the presence of the pipeline; It should conduct the surface peak velocity above the pipeline as the main control index in routine vibration monitoring of pile foundation construction adjacent to buried pipeline; by positioning analysis of impacting vibration source, the rupture area of rock and soil around the pipeline caused by the vibration was determined, and security measures for pipeline protection was proposed. It provides a new method of control technology for pile foundation construction.