Advanced Materials Research Vols. 243-249

Abstract: Red mud is the waste which is generated in the process of extracting alumina from bauxite. In this paper, results showed that aerated concrete preparated with red mud, fly ash and other solid industrial waste, its strength can reach 2.5 ~ 5.5MPa, density of 550 ~ 800kg/m³, radioactive limit meet the requirement of material to the wall. Use of red mud to produce aerated concrete is an effective way with good environmental and economic significance.

Abstract: The characteristics of deformation and strength of soils under the plane strain condition can be simplified as a two-dimensional problem. How to easily and reasonably determine the value of principal stress in the direction of plane strain is the key point. Based on the Elastic-plastic stress-strain relationship for soil and test data under the plane strain condition, it is assumed that the relationship between principal stresses in plain strain direction and the principal stresses in the other directions is bilinear. The parameters of bilinear function are determined by one-dimensional consolidation and failure state. The principal stress in plain strain direction is expressed as a function of stress states and material properties. Compared with test results, the rationality of the proposed bilinear principal stress function is testified.

Abstract: With the depth increasing continuously, more complicated of geological conditions, will make intersection in deep soft rock roadway is very difficult to support. In order to solve the intersection problem of difficult to support, combined with the third levels of the Fifth Coal Mine of Hemei, the coupling supporting design—anchor-mesh-cable + truss to control stability of crossing point—is proposed. Based software of FLAC3D, simulate the program applicable in deep soft rock roadway intersection. Application results show that the coupling support technology of anchor-mesh-cable + truss can effectively control the deformation of intersection in deep soft rock roadway.

Abstract: A series of drained tests of ISO medium sand were performed to study the onset and formation of shear band. Using the digital image processing technique, the multifunctional triaxial equipment of GDS was improved. Strain isogram and local stress-strain relation at every sampling time point were recorded based on the improved equipment. The onset of shear band was from inhomogeneity of soil, while the inhomogeneous deformation can be induced by end friction and initial defect. Based on results of global stress-strain and local stress-strain relation, the end friction effect was found to have a strong influence on the radial strain. The macroscopic non-uniform sample was obtained by putting silt clay block into sand sample, evolution of shear band during the loading process showed that the discontinuation of stiffness formed at interface of two materials, with inhomogeneous deformation developing, macroscopic continues shear band fully formed.

Abstract: The method of composite stiffness principle and biparameter for laterally loaded pile was used in this paper to calculate the amplitude of deflection and rotation of pile on the ground when the vibration frequency of dynamic load is equal to or close to the natural frequency of pile, i.e. when the pile is in the state of resonance. And the amplitude of the maximum bending moment and its location was also calculated. Then the finite difference method which is simple in principle and easy to program was used to calculate the displacement, soil side resistance and internal forces of pile under horizontal dynamic load. By choosing reasonable parameters, rotation, displacement, and the maximum bending moment of hollow concrete pile and solid pile under the same dynamic loads at pile top in the same geological conditions were calculated respectively. On this basis, the performance differences between hollow pile and solid pile were analyzed. Some advantages of hollow pile were obtained. This research provides a theoretical guidance for the using of hollow pile in engineering.

Abstract: The excavation and support problem of deep foundation pit is very interested by construction engineers with the development of the high buildings in cities and exploration utilization of the underground pace. Stability and economy are the most important problems in deep foundation pit support. This paper mainly studied on stability and economy of steel sheet pile support structure. The steel sheet pile support technique was fully introduced and analyzed here, using a combined method of theoretical guidance, calculation analysis, engineering application with finite element program simulation and market investigation.

Abstract: Present methods for stability analysis of underwater slopes are mostly confined to laboratory experiments and limit equilibrium method. This paper is based on strength reduction method, considering the deformation parameters of rock mass to discuss the stability of underwater slopes. Comparing the consequences, the sliding planes and safety factors agreed well with the result of limit equilibrium method. The applicability of strength reduction method for underwater slopes stability was well proved. When analyzing after changing the water depth, it was showed that there are more erosion effect induced and reduction for the parameters of rock mass, but little influence on the safety factor of underwater slopes.

Abstract: Creep is an important mechanical property of rock, and it is closely associated with the long-term stability of rock landslides. To further discover the sliding mechanism of the horizontal-strata landslides, red sandstone samples were taken from Erchengyan horizontal-strata landslide bedrock in Wanzhou, and triaxial creep tests by step loading technique were conducted on red sandstone with RLM-2000 triaxial rheology test machine. The triaxial creep tests lasted 1180h under the constant temperature of 18.5±0.5. Boltzmann superposition was adopted for test data processing, and an improved translational coordinate method was used to reduce the degree of the data distortion. With the improved method, a complete creep curve of red sandstone strikingly consisted of three stages, namely, attenuated creep stage, steady creep stage and accelerated creep stage. The complete creep curve of red sandstone can be fitted by Burgers model.

Abstract: Based on the Generalized Plastic Mechanics (GPM) and strain gradient-dependence of yield surfaces, the differential expressions of the volumetric and shear plastic strains are constructed, then the Generalized Gradient-dependent Plastic Mechanics (GGPM) is established to describe the strain localization characteristics and the basic mechanics characteristics of geo-materials. In order to discretize the controlling equations and the boundary conditions of analyses filed, an increment functional in which the displacement and plastic multipliers are independent variables was constructed to build up the variational principle of GGPM. Both the displacement and the plastical factor are discretized in space. A set of non-linear equations taking the displacements and the plastic factors of nodes as the unknown variables are obtained to solve the new proposed mechanic model. The boundary condition and the increment algorithm are also given. The numerical examples indicate that: (1) when strain localization appears,the plastic shear strain and the plastic volumetric strain mainly concentrate in localization band; (2) the mesh- dependency does not appear any more when the size of mesh changes; (3) when the parameters reflecting localization increase,the width of the strain localization band will be wider obviously.

Abstract: The mechanism of one small slide in the FuChang road at the Taihang mountain is analyzed with the comprehensive exploration methods. It is brought forward that the small slide is a shallow layer crushed stone slide with the type of drawing – enlarging outside. The vertical prestressed anchor retaining earth wall is applied for safety correcting the slide with the economical and feasible correction principle. This method depends on the vertical prestressed force, pressed on the earth wall body which is made by the anchor in the foundation, to balance the sliding force of the slide mass. The design thinking of the vertical prestressed anchor retaining earth wall is analyzed in details and the construction technology and technique essentials is introduced in this paper. The efficiency of the method is indicated by its well correction result.