Applied Mechanics and Materials Vols. 170-173

Abstract: In order to study the influence of cavity above the tunnel on stratum deformation and failure in urban tunnelling, the model test method was adopted based on the parameters of the stratum and tunnel section size in Beijing subway. The stratum responses were obtained under the conditions without ground cavity and with ground cavity above the tunnel. The responses include the stratum stress distribution, stratum settlement law and stratum failure process. It was concluded that the existence of ground cavity above the tunnel worsened the stratum condition and accelerated the progress of stratum deformation and failure. Furthermore, the failure began from the cavity and the damage scope was bigger than that under the condition without cavity according to the test results. The research results can be referenced for the similar tunnel engineering.

Abstract: Abstract. In jiangxi red XiaShan highway tunnel interval for engineering background, the key research different scheme for tunnel construction process between them the mechanical behavior of rock and analyzed. For small interval double hole parallel tunnel between them the complex rock stress state, the finite element analysis software for using the numerical analysis method is buried deep in the condition of small interval period of bias by different construction scheme of tunnel numerical simulation. To meshshotcreting firstly method, CD method, up and down steps method, the construction method of different displacement and deformation of the stability of surrounding rock and the comparative analysis. Analyze the different schemes of before and after the surrounding rock tunnel excavation and supporting structure composed of each other of the unity displacement change rule. Put forward the tunnel between them weak rock the concept, more explicit the engineering geological conditions of weak rock tunnel clip to control surfaces. And on the basis of guidance for engineering construction, in actual construction which has obtained a better effect. The result is of a similar project design and construction to provide the reference and the model.

Abstract: Based on the theory of viscoelasticity and the principle of interaction between surrounding rock and structure in unload state, analytical solution of the stress field and displacement field of the frozen wall is obtained. Calculation results of the stress and displacement fields suggest that radial stress and displacement in the sidewall are very large within 15 days after pouring concrete of the outer shaft wall, which is proved by the fact that engineering incidents such as shaft wall rupture happen exactly at this time. The results also indicate that radial stress at different points in frozen wall all tend to the imposed loads on outer frozen wall finally, and that means the frozen wall is fluidized. This calculation theory can be used in the design of frozen wall in deep alluvium.

Abstract: Aiming at collapse in the excavation of tunnel in western Henan, the measures including cement grouting and leading conduit are proposed to be used in the treatment of collapse, and the processes of the treatment is numerical simulated. Comprehensive analysis shows that the broken surrounding rock strength has been improved significantly, and it worked fine after being treated.

Abstract: The infiltration capacity is a decisive factor to ensure the effective operation of groundwater reservoir. This study analysis the infiltration capacity variation and its factors based on the data of infiltration test in Hutuo River Groundwater Reservoir. The results show that, there is a high infiltration rate in the alternative field, the infiltration rate is 3m/d, and decreased by 50% as 1.4m/d 6 days later; the contrast of soil permeability, vertical permeable rate of aerial zone, permeability of saturation zone between pre-test and post-test show that, the vertical permeable rate of aerial zone and permeability of saturation zone vary little, the descend of soil permeability is the main factor of the infiltration capacity decay.

Abstract: This paper mainly uses finite element method (FEM) to research how the bent-height influence on dynamic characteristic, acceleration reaction, dynamic water pressure, dynamic stress reaction of the aqueduct-water coupling structure seismic performance. Through calculation and analysis some significant results were obtained.

Abstract: This paper use FLAC3D method to analyze the dynamic response of some levee that has a cavity in it under the condition of no damping. The results show that there are good corresponding relationships between the shear wave spread characteristics, the horizontal position and depth of the hole, and the specific location of the holes in the levee can be determined. The results can provide references to the test of holes in levee.

Abstract: Numerical tests are carried out to research mechanism of hydraulic fracturing. As well as that: reservoir storage leads to bending of the embankment dam because of water pressure, especially upright core wall when reservoir storing rapidly, and then bending leads to vertical stress unload. The macro and micro mechanism of soil fracturing in unloading condition are analyzed by the Distinct Element Method (DEM). The results indicate that: (1) Initial stage of specimen will lead to volume response of dilatancy in the unloading condition. Actually, volume response is expressed as dilatancy consistently with the low level confining pressure and is expressed as dilatancy then compression latterly with the high level confining pressure. It suggests that the unloading condition may be a factor for granular material cracks. Particularly, not only the unloading condition with low level confining pressure leads to cracks, but also it helps the cracks development. So we argue that: unload condition, such as reservoir storage is a factor for hydraulic fracturing in the embankment dams, especially in low level stress areas. (2)The strength of soil in the unloading condition decreases than the loading condition, which contributes to hydraulic fracturing.

Abstract: City intake water pumping stations are restricted by bank slope conditions of water source areas and land use restrictions etc. Intake structures are difficult to be arranged in accordance with the requirements of hydraulic conditions. Therefore, adverse flow phenomena such as bias flow, recirculation and vortex are easier to generate in the forebay.The adverse flow imparts an adverse effect upon the pump inlet condition, so as to negatively influence safe operation of the pumping station. Physical models were tested according to layout characteristics of a city intake water water pumping station to research the reasons of bad flow conditions occurred in the caisson type forebay. The study found that the bottom sill in the forebay would improve the inflow pattern. The test results showed that the sump of the pumping station could effectively improve the flow pattern in the forebay and improve the efficiency of the pump operation.

Abstract: The water regulation system for the Mid-route of the South-to-North Water Transfer Project is a systematic project with a complicated structure, higher technical difficulty, more functions and wide scope involved. This paper describes the overall framework of system design and system logic, analysis of the system applications, application components and technical support platform architecture, data acquisition, storage and management system. This article describes the communication system, computer network construction and operation of the physical environment in order to provide reference for water regulation system building automation