Applied Mechanics and Materials Vols. 580-583

Abstract: A series of tests on the soil water characteristic curve through moisture balance method were conducted to study the effects of temperature, sand mix ratios and dry density on the soil water characteristic curve of bentonite-sand mixture. The test results show that with the increase of temperature, the water retention capacity of the mixture significantly decreased. Within the test control suction range, sand mix ratios at the low suction had obvious effects on the soil water characteristic curve and at high suction the effects gradually decreased. Dry density had no effects on the soil water characteristic curve of bentonite-sand mixture. In accordance with the test data, an experience model of soil water characteristic curve of bentonite-sand mixtures considering temperature and sand mix ratios is established.

Abstract:

The Yanqianshan iron mine is preparing to transform from an open-pit mine to an underground mine. We adopt the non-pillar sublevel caving approach to exploit the particularly thick steep ore bodies within the range from -183 m to -500 m from top to bottom. According to the features of ore body distribution and the approaches of exploitation, we expect that underground mining will result in the loss of stability on the northern slope of the open pit, causing traction-type landslides. Moreover, along with increasing the depth of the mining operation, the range of slope failure will continue to expand and further affect the safety of drainage features and roads distributed on the north side of the open pit. For this purpose, we select four sections along the trending direction of ore bodies and apply the limit equilibrium method to predict the failure process and characteristics on the northern slope according to the stratified mining process.

Abstract: In this article, we design an experiment about model piles to study their bearing capacity and deformation properties under uplifting load of different angles, model piles include the equivalent-diameter pile, the squeezed branch pile with single plate and the squeezed branch pile with two plates. The test shows, the bearing capacity of squeezed branch pile is higher than the equivalent-diameter pile, and its plates can resist the horizontal load on the top of pile better.

Abstract: Combustible ice is a kind of efficient and clean energy that has the potential to be exploited in the future, exploiting combustible ice needs to understand its mechanical properties. Combustible ice is another important feature of soil which is different from soil, in order to correctly understand the distinction, this paper using soil mechanics triaxial test method, to study the mechanical properties of combustible ice. Different from previous study, this article put forward the concept of simulated combustible ice, namely through baking powder, sodium chloride, and Marine sedimentary soil to simulate flammable ice, explore a new method for sample preparation to study the mechanical property of combustible ice.

Abstract: In combination with Rankine's earth pressure theory, a weak form quadrature element formulation is established for analysis of diaphragm walls. Results are compared with those of Paroi2, a finite element software package for diaphragm walls, to demonstrate the effectiveness and the advantages of the present formulation. Accurate results are obtained with only a few weak form quadrature beam elements, contrasting with dense finite element division that is needed for complex load distributions over the diaphragm wall.

Abstract: In this paper, we present a numerical modeling of chemo-mechanical behaviour of sandstone. An internal variable is introduced in this model for the purpose of describing pH effect on elasto-plastic properties. A new chemo-elasto-plastic model is proposed for sandstone. The proposed model is applied to predict material responses in triaxial compression tests of sandstone after soaking in different pH acidic solutions. We concluded with good agreement between numerical simulations and experimental data.

Abstract: This paper developed a critical-line-based method for predicting the occurrence of landslides using two rainfall indices, the rainfall intensity and the accumulated rainfall, based on four landslide case histories recorded in a county. Specifically, the rainfall records of the four cases were used to compute the 60-minute rainfall intensity and accumulated rainfall prior to the occurrence of landslides. Although the meteorological and geological conditions as well as other crucial factors are not considered in the development of the intended model, the analysis results indicated that the developed critical-line-based predictive model can reasonably identify the boundary between occurred and non-occurred zones. The developed model has the potential to be a useful tool for predicting the occurrence of landslides according to the rainfall conditions.

Abstract: Mechanisms of the distortion of deep excavation in soft clay are recommended on the beginning. Plane FEA method is combined with back-analysis from displacement on this paper to establish a dynamic prediction system of the distortion of deep excavation, which is proved to be viable by practice. Combining with the idea of process control, a process control model of the distortion of deep excavation is established on this paper. It is divided into three parts: advance control, observation and dynamic prediction, process control in the construction.

Abstract: This paper analyzes an engineering in an area of China which was processed by vacuum preloading technology in the silt soft soil. This engineering was used rigid supporting structure technology of piles in row and bolts for large area of deep foundation pit supporting. It compared the realistic measure soil pressure and theoretical concluded soil pressure, and got the soil pressure distribution mode which is suitable for silt soft soil processed in this way. The conclusion can provide a reference for similar supporting structure system to calculate earth pressure.

Abstract: Most of the studies on cavity expansion are about the analytical solutions of the stress distribution, and not related to the effect of soil properties on earth pressure. Aiming at the problem, the change law of passive earth pressure is analyzed by using the Mohr-Coulomb model, and the formula of earth pressure is summarized. The error value of calculation and simulation is small that the formulas can be directly used in practical engineering.