Search

Similar materials of rock mass and cement mortar were prepared and similar bolt was selected to study the anchoring mechanism of rock slope. Three kinds of drawing specimens with different anchoring lengths were constructed, and static drawing test analyzed the shear stress distribution on two anchoring interfaces of bolt-mortar and mortar-rock mass. The axial force decreases exponentially with the increase of the anchoring length. The shear stress of the two anchoring interfaces presents a unimodal distribution that first increases and then decreases along the anchoring length. The three stages of the anchor solid drawing processare as follows:the interface undergoes elastic deformation, plastic deformation, and debonding and slip. The shear stress distribution on the anchoring interface of rock slope is obtained for the first time by similar model tests. A new anchoring mechanism is proposed to become not only an important reference value for the related tests but also for the design and construction of the slope anchorage.

By analyzing the characteristics of expansive soil from Pingdingshan, China, the shear strength parameters at different water contents, dry densities, and dry-wet cycles of expansive soil are obtained. It is found that, at higher soil-water content, the internal friction angle is 0° and the shallow layer of expansive soil slope will collapse and destroy; this has nothing to do with the height of the slope and the size of the slope. The parameters of soil influenced by atmosphere are the ones which have gone through dry-wet cycles, and the parameters of soil without atmospheric influence are the same as those of natural soil. In the analysis of slope stability, the shear strength parameters of soil can be determined by using the finite element method, and the stability coefficient of the expansive soil slope can be calculated.

An indoor model of expansive soil filling slope is tested in Pingdingshan city, Henan province, China. Using temperature and humidity detectors, earth pressure cells and so on, the static evaporation - rainfall infiltration cycles are tracked and monitored in the climate condition. The study suggests that atmospheric temperature is the direct cause of soil temperature. Due to the convection heat transfers, the surface temperature of the soil changes rapidly, and the temperature change of the heat transfer to the interior has a hysteresis phenomenon. Under surface evaporation conditions, the greater the depth is, the smaller the change range is in water content. Water loss rate is related to soil, air flow, temperature and humidity, cracks, soil water holding capacity, permeability and other factors. The change of stress in the expansive soil slope is the result of the joint action of soil water content, nature and climatic conditions. Due to the early erosion of rainfall, soil pressure is obviously attenuated. The soil pressure is on the rise due to the effects of rainfall infiltration and expansion force in the late rainfall. In the engineering, the key to prevent and cure engineering disaster of expansive soil is to improve the deformation characteristics and reasonable drainage of expansive soil.

An empirical numerical model was established for analysing the temperature variation of pavements in Xi'an area of China. This model can consider the influence of solar radiation, atmospheric temperature and humidity. It was verified by comparing the calculated and measured temperature of the natural ground surface. The effect of seasonal variations of temperature on asphalt and concrete pavement surfaces were then calculated. The temperature distribution of both asphalt and concrete pavements in January and July was investigated using the model. For each type of pavement, four groups of different pavement materials were considered to investigate the influence of thermal parameters for pavement materials on the temperature distribution. Furthermore, the diurnal variation of pavement temperature was analysed and discussed based on the normal climate characteristics in Xi'an. The results of the analysis showed that the diurnal variation of pavement temperature is very significant and must be considered in the design of a pavement.

According to the existing theories of soil mechanics and fluid mechanics, as well as the features about the water and soil curves of unsaturated expansive soil. It is obtained the equations about gaseous water transfer and liquid water transfer of unsaturated expansive soil. It is be seen from coefficients in the equation that water migration bringing water content changes relating to moisture gradient, moisture level, temperature, matric suction, as well as soil density and the ratio of the volume. In different soil the water curve parameter is different, then the coefficients of differential equations is also different. As a example calculation using this equation on water content changes caused by gaseous wate migration, gaseous and water mixed migration, we see that the computed results are consistent with the experimental results very well. It is verified that the equation is rational.

On the basis of the gas state equation, fluid mechanics, soil mechanics theory and characteristics of unsaturated expansive soil. The water vapour flow per unit area method of calculating is geted. It revealed that the water vapour flow is co-decision by temperature, soil and water situation. and it is directly proportional to the suction gradient. and it has non-linear relationship between soil porosity, water saturation, the absolute temperature and suction. According to the calculating of test data to illustrate the feasibility of the method of calculation, in order to further study lay the foundation for migration of water vapour.