Advanced Materials Research Vols. 446-449

Abstract: Although ABAQUS is one of the most powerful non-linearly finite element software, it is lack of interface Duncan-Chang constitutive model, which is one of the generally used soil numerical method in China and worldwide. Subsequently, ABAQUS can not widely used in soil numerical method. To improve this situation, a new interface Duncan-Chang constitutive model was developed based on the preliminary direct shear test results through secondary development. Combined with practical engineering, the efficient model was established. Compared with smooth geomembrane/geotextile interface, the shear stress of reinforced geomembrane/geotextile interface increases obviously, and the sliding displacement decreases obviously. It supports our assumption that the reinforced geomembrane can improve interface shear strength and stability of liner system.

Abstract: The experimental study on the case of bond failure happening at the grout-rock interface about mortar bolt, the concrete matrix is sudden destroyed when loading specimen which grouting length 60mm, compared to previous research, it is reduced by dilatancy effect when mortar is pressed out of the body, this paper analyzes the concrete axial radial pressure when mortar is pressed out and the dilatancy effect using the finite element method.

Abstract: Abstract: For the purpose of stability of surrounding rocks of tunnel during the stage of construction and operation, a series of monitoring methods and measurement are carried out to investigate performance of Heishan tunnel through selecting 5 cross sections for monitoring. Based on the monitoring data, convergence around tunnel, displacement of different points of interior of surrounding rock, axial forces of rock bolts and pressure of surrounding rock are analyzed. The characteristics of selected cross sections are useful for engineers to optimize the preliminary design of tunnel. Furthermore, the study results can be used to guide the design, monitoring and construction for future tunnels with the similar geological condition.

Abstract: Some project in Henan Province of China mainly includes high-rise residential buildings, multi-storey commercial building and the garage, and the building fields are collapsible soils which belong to non-weight grade Ⅱ. 315 static pressure PHC piles were constructed in square shape, 7 holes were drilled at the places near or close to the PHC pile, porosity ratio, weight and non-weight collapsibility coefficients were in-door tested, and corresponding calculation results reveal that: static pressure PHC piles can efficiently eliminate loess collapsibility of the fields, there are differences between the porosity ratios of experimental values and theoretical values, so the construction testing and acceptance should be based on the in-situ testing results, and these conclusions provide basis for the similar projects in future.

Abstract: Abstract. Aiming at the features of the articulated hollow slab beam bridges with transverse prestressed force, an assumption that regards the reinforced slab beam bridges as analogy orthotropic plate was proposed. The lateral flexural stiffness and torsional stiffness of the plate bridges per meter width can be calculated approximately as an average value of those of the solid section and the minimum hollow section. The longitudinal flexural stiffness and torsional stiffness per meter width remain the same as the original ones. The modified G-M method for calculating the strengthened bridge was proposed. Example as a typical hollow slab bridges, the lateral load distribution influence-line after strengthening bridge obtained by using modified G-M method. The numerical analysis before and after strengthening bridge by using FEM was complete to gain lateral load distribution influence-line. It shows that the values predicted by the proposed modified G-M were matched with the results by the FEM after strengthening bridge. It shows that the method strengthening articulated hollow slab beam bridges by exerting transverse prestress steel wire on them proved to be effective and the presented modified G-M theory to be right.

Abstract: For roadway driving along next goaf of strip pillar second mining, being influenced by the abutment pressure of previous coal mining face and main roof breaking rotary deformation, the surrounding rock deformation is serious and the control effect of ordinary bolt supporting on the general stability of roadway driving along next goaf is poorer. According to the concrete geological and technique condition of the 2351 second mining strip pillar in Daizhuang Colliery, adopting the united support pattern combined high strength bolt of levorotatory continuous thread and anchor of low relaxation prestress, the safety of the roadway can be ensured and the stability of the roadway surrounding rocks can be improved. It is of significant reference meaning for bolting support of roadway driving along next goaf of second mining strip pillar under similar condition.

Abstract: The interface interaction between geogrid and soil is one of key issues on stability of geosynthetic-reinforced soil structures. Comparative analysis of properties of geogrid-clay interface under the different kinds of geogrid, different normal stresses, speeds of pullout and water contents of clay are conducted by medium-sized pullout tests. The tests results showed that ultimate pullout force of geogrid, interfacial cohesion and frictional coefficient are significantly affected by various water contents of clay. Ultimate pullout forces of geogrid tending to remarkably difference when subject to different normal stresses at lower water contents, and frictional coefficient of interface decrease with the increase of water content, interfacial cohesion has a tendency to increase followed by decreasing with increase of water contents. Moreover, the curves of load and displacement possess three piecewise consisting of linear increase, non-linear increase and ultimate pullout, and as water content increase interval nonlinear changing stage is not conspicuous.

Abstract: Mechanical properties of cemented reticulate red clay were studied in present research. Test results show that: (1) shear strength of cemented reticulate red clay increase exponentially as the increasing of cement content; (2) shear strength of cemented reticulate red clay decrease polynomially as the increasing of water content; (3) mechanical properties of cemented reticulate red clay affected significantly by curing time and curing confined pressure. In order to study viscous properties of cemented reticulate red clay, cemented reticulate red clay specimens were compressed in triaxial chamber at different shear rate. Results of the compression tests show that it is obvious that the axial strain-deviator stress relationship of cemented reticulate red clay affects by the strain rate.

Abstract: The aeration-vacuum dewatering method is a new kind of solid-liquid separate technique. The filter clogging problem in the routine vacuum dewatering procedure of sludge can be solved by the method. This method is used to dewater the sewage sludge in this paper. Through the dewatering model test of the sewage sludge with this method, the change law of the solid content and the volume of the sewage sludge are studied. The dewatering effect of sewage sludge is got further more. The test results indicate that there is a great promotion for improving the solid content and reducing the volume by using the aeration-vacuum method.

Abstract: The damage of debris flow effected on highway subgrade, pavement, protective structure, bridge and culvert laid on debris flow impact fracture and buried damage. Thus far, research on debris flow burying mechanism is still fuzzy. According to the two-phase flow theory of debris flow deposit, analyzed the consolidation mechanical mechanism of highway debris flow deposit. On the basis of Terzaghi one-dimensional consolidation theory, established the consolidation formula, which described the change process of excess pore water pressure, consolidation degree, settlement and compression with the consolidation time and deposit size, and then verified the correctness and feasibility of the formula by the indoor consolidation test. It adopted these results and combined it with the field survey data, it could develop a proper program for emergency mitigation of highway debris flow buried disaster more quickly and accurately.