Applied Mechanics and Materials Vols. 353-356

Abstract: The influencing factors of grouting diffusion in broken rock mass were divided into four classifications: grouting pressure, grouting time, permeability coefficient and grout viscosity. Relations among similar factors were expressed to each other using an equation. Empirical formulas of relations among grout water-cement ratio, viscosity and time between the joint density of broken rock mass and permeability coefficient, and between water absorption and permeability coefficient were established. The differences among the four diffusion radius formulas grouting in porous continuous media were compared. A new empirical formula of diffusion radius was obtained using multivariate nonlinear fitting analysis based on the mean value of the four empirical formulas. The tests of grouting diffusion in broken rock mass were done in the field. The mean empirical formula is consistent with the measured value of the field tests on grouting diffusion radius, which provide a reference for the design of grouting into broken rock mass.

Abstract: This paper analyses the stability of a highway slope in Yunnan by using the FLAC3D numerical software. To simulate the stability coefficient only considering the gravity loads and also taking into account the action of groundwater and then in comparison with the result calculated by the limit equilibrium method consider the influence of groundwater , the results show that the slope in a state of instability with the effect of groundwater. Then use anchorage to upgrade the slope, and the slope in a stable state after reinforcement. The simulation results have certain reference significance to the slope management.

Abstract: The stability of soil slope is a common engineering problem and many scholars and experts have done abundant works on it since 1940s. By utilizing limit equilibrium equations, some slice methods had been proposed to search the most dangerous sliding surface, and they obtain enormous success. This article focuses on the fact that residual sliding force is an important parameter to design resistant structures in Chinese engineering practice. While the most dangerous sliding surface does not coincide with the sliding surface which the largest residual sliding forces locates on. So we compile the program to find the sliding surface by maxing residual sliding force. And some sample examples are executed, the surfaces comes from new method are compared with surfaces form Janbu Method. Some interesting conclusions are obtained.

Abstract: To determine the ultimate load capacity of drilled shaft socketed into rock under axial compression loading, it is necessary to predict both the ultimate side shear resistance and the base resistance based on field load test or/ and laboratory tests. In geotechnical engineering there are several methods proposed the relationship between rock properties (the unconfined compressive strength) and the ultimate side shears resistance and base resistance. This paper presents the review of design methods of ultimate side shear and base resistance for rock-socketed pile. These empirical functions depend on the socket type and the range of the unconfined compressive strength of rock.

Abstract: Experimental studies were conducted on unidirectional and multidirectional freezing of artificial soils in a rectangular cavity. The ice lenses were observed through transparent plexiglass plate. Temperature gradients in soil specimen were obtained during freezing process. The experimental results indicated that the temperature gradient may change the shape of ice lenses. The amount of frost heave of multidirectional freezing was less than unidirectional freezing, so multidirectional freezing mode is helpful to restrain vertical frost heave.

Abstract: Swelling and shrinkage due to moisture-change is one of the expansive soils characteristics, which is similar to the behavior of most materials under thermal effect. The stress is defined as moisture-change stress and is adopted to analyze swell-shrinkage deformation based on the elasticity mechanics theory. A FEM program is established which is used to calculate the stress caused by moisture-change considering the defect of theoretical calculation. The stress via FEM program can be accordance with the actual characteristics and the moisture-change is more applied extensively.

Abstract: In case of highway road construction often beneath existing overpass project, the filling of neighboring embankment may cause lateral displacement of bridge piers, which seriously threaten the safety of bridge. One case history, for inclination disease of overpass bridge piers in soft soil area, was presented. Aiming at the deformation of piers caused by the neighboring embankment construction, the displacement feature of bridge bearings were tracked and measured by site monitoring, and the damaged position of piles were clarified with low strain dynamic test. For these geological traits, the reasons of the inclination were analyzed. And the rectification method of applying surcharge load for smaller deviation (50mm) and the rectification method of pushing combined traction for serious deviation (>50mm) were respectively put forward on the basis of the lateral displacement statistics of bearings and the analytical standard set by Bozozuk. Site observation indicates these rectification methods can achieve the desired results.

Abstract: In order to analyze the influence of bolt supporting parameters on the stability of slope, based on the limit equilibrium method to establish model of slope and calculated the safety factor of slope. Research shows that: (1) As the bolt length increases, the safety factor of slope increases gradually, then the length of anchor bolt can be used as the design length when the safety factor can meet the standard requirement.(2) With the increase of the anchor Angle, the safety factor of slope present the trend of first increasing and then decreasing, when bolt spacing increased to a certain value, the safety factor of slope reduce significantly.(3)In this paper, the analysis method of slope bolting parameters on its effect to the stability is simple and strong operational, which can provide a reference for related engineering personnel.

Abstract: Calculation methods for active earth pressure of retaining wall are analyzed and discussed, and then based on energy conservation principle, one formula about calculation of active earth pressure was deduced which was illustrated with two engineering examples. The results suggest: compared with other limit equilibrium method, this method is closer to practical action and relatively simple, and is applicable to any case calculation for active earth pressure of wall retaining, so has high promotion value.

Abstract: Great region discrepancy exists in natural soil, while analysis and calculation of stability against upheaval of foundation pit in current specifications is only to soft soil. In order to study the stability against upheaval of foundation pit bottom in different geological conditions, FLAC3D numerical analyzing software is adopted to calculate and visualize the influence that several factors cause to stability safety coefficient, and contrast and checking is also made with current analysis and calculation methods and normal formula of stability against upheaval of excavation. The study shows that : a increase in soil’s cohesion,internal frication angle and embedded depth can develop the stability against upheaval of foundation pit.