Advanced Materials Research Vols. 594-597

Abstract: As to the time effect of prestress in bolt in geotechnical engineering, the stress distribution in fully-grounded MFRP bolt and its trend influenced by rock rheology is obtained by FEM. The Burgers body which is able to model the primary and secondary creep regions of the rock mass is applied to analyze the time effect of prestress in MFRP bolt. The results show that rock rheology has a great effect on MFRP bolt stress.

Abstract: This paper summarizes the possible supporting forms of deep excavation which will provide some useful suggestions for retaining structure pattern selection based on the geological characteristics of foundation soil in Kaifeng. Then combing with the irregular-shaped deep excavation of certain civil air defense engineering, a comparatively effective waterproof measure is proposed. Moreover possible problems encountered in the process of construction are discussed, and their corresponding solving ways are illustrated systematically. The research results will contribute to choose the supporting pattern and water sealing measure for deep excavation in Kaifeng region.

Abstract: In order to reduce both uneven settlements and construction duration, researches on pile-supported composite foundation of highway were carried out. When the groundfill is higher than the critical height（1.35 times space between piles）, a complete geostatic arch is formed in the pile-supported composite foundation, which could significantly reduce the uneven settlement. Grids installed at the bottom of embankment could markedly reduce the side displacement and increase the stability of embankment, multilayer grids with layout of loose on the top and dense at the bottom prefer to single layer grids. Plastic drainage board makes up well-functioned drainage system, which can shorten the dispersal time of pore water pressure and accelerate the consolidation of soft soil to shorten the construction duration.

Abstract: In this paper, a series of true triaxial tests indoor with acoustic emission mornitoring were conducted and the characteristics of acoustic emission rate and energy releasing rate in the section adjacent to failure were gained. According to the different characteristics of acoustic emission rate, we divided the events rate into three types which were main shock, foreshock-main shock and cluster shocks. And then, a prediction method for hard rock was put forward according to different events rate types based on the trends of AE signals in the section adjacent to failure for hard rock.

Abstract: Landslide is a form of moutain land diseaster. Among all the natural factors, torrential rainfall becomes the major contributor. This thesis, through the analysis of 1414 cases in zhejiang province, the precipitation in 10 days before landslide, aims to establish the landslide forecast model that triggered by torrential rainfall, which can also contrubute to the research on the mechanism of landslide caused by torrential rain.

Abstract: Through numerical calculation on the stability of powerhouse slope by the coupling fluid-solid model of ABAQUS software, stability of powerhouse slope under the operation water level of Tianhuaban hydropower station has been evaluated. The results show that influence of pore pressure and the pore fluid effective velocity vector under the operation water level of Tianhuaban hydropower station has been limited on the scope of powerhouse slope from elevation 971m to 990m; the displacement concentration phenomenon has been existed on the scope of powerhouse slope from elevation 971m to 1010m, but the value of total displacement is smaller; influence on the stability of powerhouse slope under the operation water level is weaker; and on the scope of powerhouse slope from elevation 971m to 990m, the seepage phenomenon may be happened, and the waterproofing measures on this area must be strengthened. The achieved results can provide a research foundation for the stability of hydropower station slope on the periodic pore pressure disturbance.

Abstract: With the saturated - unsaturated seepage theory, Hualianshu landslide is seepage numerical simulated by the finite element method .The changes of Hualianshu landslide seepage are subject to the impact of rainfall and reservoir water level's changes.The formation and variation of the slope seepage field under rainfall infiltration have been come to, providing a basis for analysis of slope stability and landslide prediction.

Abstract: Based on BP neural network, simulation analysis of damage location and degree of unsaturated soil embankment slope under rainfall infiltration are made using finite element method. The simulation model is established by rainfall infiltration statistical characteristics as the main input vector. The results show that the artificial neural network can accurately identify the damage location and the damage degree of the slope.

Abstract: Taking the granite residual soil embankment of Fujian Province as an example, this paper investigated the moisture migration mechanism in granite residual soil embankment based on the finite difference technology. The results show that the moisture migration of the shallow layer of the embankment displays up first and down later in dry seasons. In rainy seasons, the negative pressure head of the embankment’s upper soil increases, and range of rainfall variation of the initial period is much sharper than the later period. Meanwhile, at the toe of slope, the rain firstly supplies the groundwater, making it a weak location. After the rain, the contour line of negative pressure head in the upper embankment gradually becomes sparse, and the gradient gradually decreases in the embankment. The fluctuation of negative pressure head on foundation surface decreases with the depth of groundwater. As to the low embankment, the change of the embankment moisture mainly depends on the external weather conditions when the groundwater level is deep and the moisture is mainly affected by groundwater when the groundwater level is shallow.

Abstract: Dredged soil once was considered as the waste and abandoned, which had resulted in serious environment pollution and high costs. Since the viewpoint of “Utilize Dredged Soil Valuably” was proposed in 1980s, the dredged soil has been used as the hydraulic fills in land reclamation, which can meet the requirements of the booming land expansion. However, most of the fresh hydraulic soil is the floating or fluid mud, and has high water content but little bearing capacity, so it is difficult for the traditional treatment methods to improve the super-soft foundation. Based on the drainage and consolidation theory, the rapid improvement technique without sand cushion for the shallow base was developed and has been applied successfully in engineering practices. The applications showed that the rapid improvement technique improved the bearing capacity of super-soft foundation substantially, and compared with the traditional vacuum preloading method, this new technique is more environment-friendly and cost-saving.