Abstract: Factors affecting the supporting structure in a soft soil foundation pit are analyzed in this paper. Based on the information obtained from accident investigation, design factors and construction factors, such as insufficient embedded depth of pile and insufficient anchor pullout resistance, are discussed in detail. The analysis and conclusions can serve as a good reference for similar projects design and construction.
Abstract: Based on the safety and durability in the cement soil engineering about the pits anti-seepage, embankment impermeable walls and subgrade strengthening in the frozen regions and the retaining walls in foundation pits, the experiments on the compressibility about the cement soil under freezing-thawing cycle, infiltrated and other environmental-action conditions have been carried out and the influential laws of environmental actions on the compression parameter of cement soil have been obtained. The results show that the various environmental actions may have influences on compressibility of cement soil at different levels, and the environmental effects on the compressibility of cement soil in the engineering applications and designs, such as impermeable walls or in the frozen regions, should be taken into account; and the void ratio and the compression parameter will increase with the increase of freezing-thawing cycle times and infiltration time but the compression modulus will decrease with the increase of freezing-thawing cycle times and infiltration time so that the curve regression equation about the void ratio, the compression parameter and compression modulus varying with the freezing-thawing cycle times and the infiltration time has been established. The results are significant and valuable to the safety and the durability of cement soil engineering.
Abstract: In this paper, the effects of multiple aquifers on the calculation of bearing capacity of foundation are represented. One side is how to ascertain the maximal influence depth of underground water, and the other is which to take from the unit weight of soil in the condition of multiple aquifers.
Abstract: The presence of high-temperature air-steam mixes and their transport is the most important factor controlling the security reliability of nuclear containment vessels during a loss of coolant accident. Total accumulated amount of radioactive substances and their hazards cannot be ignored, although the release process through non-cracked structural concrete is very slow. Through established models of flow through structural concrete of containment vessels, permeability coefficients and leakage rate under steady and accident state are discussed in this paper. Comparison results of tightness show that properties of structural concrete applied to containment vessels should be strictly controlled and regulated.
Abstract: To characterize the coarse-grained soil of the fillers in Zhijiang North station of Shanghai-Kunming Passenger Dedicated Line, the vibration compaction test was conducted to study maximum dry densities under different granular compositions. Considering the non-linear relations between granular compositions and maximum dry densities, a BP neural network prediction model of which the input layer was consisted of granular compositions, grading index and fractal index was established based on the backwards error propagation algorithm and the results of the maximum dry density tests. As was improved by the adaptive learning rate method and additional momentum method, the final model established in this paper performed well in predicting the maximum dry density of the coarse-grained soil of various granular compositions.
Abstract: In the quality assessment and classification of engineering rockmass, the elastic wave velocity of rockmass has already become an important parameter. But the valve of the elastic wave velocity has obvious anisotropy which is resulted from the non-uniformity characteristics of the rockmass. Therefore, if the measured elastic wave velocity is directly applied to the quality assessment of engineering rockmass, it will not can reflect the actual engineering properties of the rockmass. In order to solve the above problem, the energy variation of elastic wave propagating in the rockmass is studied. According to the field tests of the rockmasses with different weathering degrees, the dynamic characteristics of the elastic wave such as the attenuation and the dominating vibration frequency are analysed. The relationship between the kinetic parameters and the elastic wave velocities is researched. The results show that there is a good correlation between the kinetic parameters of the wave and the weathered rockmass, which can be applied to the rockmass quality classification and the engineering geology assessment.
Abstract: This paper is aimed at analysing the slope failure model for an open pit slope. Firstly, The method of engineering geological survey is carried out for the open pit south slope. Then, the appropriate geological model is established. And the slope model of the open pits was established and solved by finite elemen program. The analysis reveals the internal sliding of the open-cut and the failure modes of bottom sliding along the base weak level. It will be an important guiding significance for the safe production of open pit coal mine.
Abstract: By means of the finite element (FE) method, the beam-shell model on elastic foundation of CRTS-I ballastless track was established. On the basis of Palmgren-Miner linear cumulative fatigue damage criterion, life cycle analysis method was used to analyze the CA mortar fatigue life under different train loads. Results show that the overall average CA mortar life is 10 to the 11th power. As the train load increases the CA mortar fatigue life decreases, the biggest drop is 4.1 percent. The danger areas of CA mortar fatigue life are on the slab ends. It is suggested that maintaining the CA mortar on the slab ends should be considered as the main task during the maintenance.
Abstract: the project is the 12 layer framework of cast-in-place reinforced concrete building roof, the C30 reinforced concrete sloping roof, slope, slope length of a bidirectional level in two forms, a gradient of about 35 °, sloping roof horizontal projection area of about 7200m2, with exhaust gas wells, gutter, roof structure is relatively complex.