Applied Mechanics and Materials Vols. 405-408

Abstract: The degree of improvement of a soft soil by stone column is due to the inclusion of a stiffer column material and the densification of the surrounding soft soil during the installation of the vibrocompacted stone column itself and the subsequent consolidation process occurring in the soft soil before the final loading of improved soil. Research study on different materials for stone column has not attracted much attention. A systematic verification of the effectiveness of different materials for stone column need to be carried out. It is an important output to be presented as a general guidelines for the selection of proper stone column material which can be used effectively and economically.

Abstract: Freezing soil is a natural phenomena in cold and mountain areas, which has great impact to the regional climate, water cycle, water balance and human activities. Permafrost against the 100 years of research show that the soil is frozen soil temperature, moisture and stress fields of common effects. Permafrost temperatures ranged from permafrost in the unique position of permafrost temperature permafrost research has become an important part of research, this paper introduces the permafrost temperature domestic development theory and research status, from the approximate calculation of the numerical analysis, measured from the scene of the computer simulation analysis, from one-dimensional to multi-dimensional theory of expansion. Permafrost temperature while the influence of the analysis, expounded the permafrost temperature on moisture movement for the promotion and transfer of water temperature counterproductive. Permafrost temperatures also study the mathematical description of the problem of note, citing the current use of the important research methods. A brief description of the permafrost study the problems that exist.

Abstract: The instability and deformation process of an example of slope is simulated using PFC here. The relationship between macro and micro mechanics parameters is established in the numerical simulation, which determines the calculating parameters.The results of simulation and the example are consistent assessment, which illustrates the effectiveness of calculation, indicates that the PFC method can search the instability and sliding surface and shows the development process of performance failure. During the process, the chain of parallel bond force fractures gradually, but the range where parallel bond fractures is larger than the instable area because of the sliding friction, which improves our understanding of slope instability.

Abstract: The three-dimensional finite element model for pile group foundation settlement analysis within soft soil pile is developed using ABAQUS. The Cap plasticity model and the elastic model are used to model the soil and the pile respectively. The contact interface elements are installed between the pile and the soil interface. The undrained loading conditions and drainage loading conditions in the soft soil piled raft foundation settlement are analyzed respectively and computation results are compared. The results show that pile group foundation in soft soil settlements increase with load increasing in both the undrained conditions and drainage conditions. The bearing capacity of the pile group under the undrained conditions is larger than that under drained conditions with the same pile group. The pile group settlement under the undrained conditions is smaller than that under drained conditions.

Abstract: The Viscoelasto-Plastic Model with Double Yield Surface is detailed deduced. Finite element equations are introduced when the deformation is considered under Coupled Deformation and Seepage Fields. Numerical simulation is carried out during the construction of the dam. All the results calculated are in accordance with the general law of the dam. Those show that it is feasible for calculating the stress field and displacement field. The method adopted and those results gained by numerical method may provide reference to engineering practice.

Abstract: This paper, which combines with the actual situation of mine, discusses the limit height and stability of the dump. Based on the basement bearing mechanism and different types of topsoil thickness, a method to calculate the height of the dump is put forward. Since the topsoil of Xichuan dump belongs to the thin type (h< h₁+h₂), and take into account of dumping technology, the limit height is determined to be 220 meters, which exceed design level (160m). And then, using limit equilibrium method based on Geo-Slope to analyze stability of the slope. The value of slope safety factor is 1.175~1.210, which is in conformity with the basic requirement of safety. In addition, the result also provides the dependable basis for the dump expansion.

Abstract: For studying the mechanism of the composite soil nailing, this paper applies FLAC-3D to simulate pure soil nailing, soil nailing-soil anchor, soil nailing-micro pile-soil anchor. The analytical results as follows: (1)Because of the anchoring of the anchor, the axial tension of soil nailing in each row is much smaller than the one in the pure soil nailing supporting, and the tension of soil nailing which are closed to soil anchor decreases obviously. (2)The extrusion action of prestressed anchor makes the potential slip surface backward shifts and the sliding radius increases, which is better for the stability of foundation pit side (3)Micro-pile increases the strength of the soil in a certain range and improves the initial stress field before the excavation. (4)The inner force of the whole soil nailing and the prestress anchor declines but the drop is not large after the establishment of the micro-pile support in advance. (5)Prestressed anchor and micropile play a very important role in controlling the deformation of foundation pit.

Abstract: Improving MSW with help of the curing agent mixed with cement, fly ash and gypsum. The unconfined compressive strength test is carried out in different conservation age on the improved MSW; Analyzing the increasing mechanism of improved MSW combined with the method of SEM/EDS. Simulating acid alkaline environment with the liquor of H2SO4 and NaOH and studying the rule of acid and alkali erosion of improved materials. The result of experiment show that improved MSW which contain cement, fly ash and gypsum is better than it only mixed with cement; The strength of improved MSW mixed with cement is better than it only have cement ,and improve more in lye.

Abstract: This paper briefly reviews the literature on the general crack formation mechanisms and the typical occurrence of crack coalescence in natural rocks, but with no particular reference to specific locations or geologic settings. The field occurrences of tensile wing cracks, horsetail cracks, anticracks and shear cracks, as well as their coalescence are described. In contrast to the tensile wing cracks which develop in the tensile quadrant, anticracks develop from the pre-existing discontinuities in the compressive quadrant. The discussion will be illustrated with plenty of field examples, supplemented by a review of commonly used terminologies.

Abstract: Drum-shaped stone tongue that there are 3 ~ 5 m thick wedge silt on the bottom formed in the junction of silt and the stone embankment by reclamation silt with mountain stone during the course of backfill. In the paper, on the basis of drills, superficia drilling holes, deep drilling holes and vibrating stop plank model, boundary stone embankment shape and soft soil layer depth were obtained, cross section of stone embankment and stone embankment boundary were revealed during the course of artificial fill, study the stone tongue shape, soft soil around stone tongue, silt characters on stone tongue bottom and reinforcement treatments were studied to obtain treatment method which can satisfy the engineering requirement and can save the engineering cost and provide mature construction technology and method for the similar subgrade treatment of sea reclamation engineering.