Advanced Materials Research Vols. 1065-1069

Abstract: For the reason of clear conception and simple physical meaning, Duncan-Chang is applied widely in civil engineering field. With the user material subroutine UMAT provided by the FEM software ABAQUS and Fortran language for programming of Duncan-Chang nonlinearity constitutive model, we can easily express the nonlinearity of rock and soil. Meanwhile, the model is applied in sedimentation analysis of high embankment. The results indicate that there is the most horizontal displacement in about middle embankment height; there is the most vertical displacement in about (1/3~1/2) embankment height; there are the most major stress and minor stress in deepest place.

Abstract: Through collecting real liquefaction in-situ data available worldwide, the correlations of influencing characteristics parameters such as PGA, water table depth, buried depth of sandy layer, SPT counts and shear wave velocity with respect to liquefaction were analyzed by means of Pearson correlation method. The correlative performance of the characteristic parameters with liquefaction was comparatively analyzed under conditions of varying buried depths, water tables and seismic intensities. The real correlations of the characteristic parameters with liquefaction were obtained corresponding to real dynamic loading, real buried condition and in-situ testing data. The analytical results show that water table, buried depth of sandy layer, SPT and shear wave velocity keep negative correlations with respect to liquefaction while correlation of PGA with liquefaction was positive. The correlations of buried depth of sandy layer, SPT were remarkable while the correlations of water table, shear wave velocity were weak. The correlation coefficient of SPT was the largest, followed by buried depth of sandy layer, PGA and water table; and the correlation coefficient of shear wave velocity was the smallest. The results presented herein can be used for updating the liquefaction evaluation methods in the codes.

Abstract: A reliability-based approach for the analysis and optimization design of anchor anti-slide pile is presented in this study by using the project cost as its objective function. The following four failure modes: tensile failure or pull-out failure of the anchor rod, as well as shear failure of anti-slide pile in the anchoring section or loading segment, are considered. The cohesion force, internal friction angle of surrounding soils, and axial compressive strength of concrete are viewed as random variables for finding optimal design parameters, such as the cross-section area or width of anchor anti-slide pile. By employing the optimization toolbox of Matlab, the corresponding design procedures are established and utilized into a practical engineering project (i.e. a slope marked as K6+525~K6+610 in Shui-Dong road, Guiyang). Results show that the proposed approach is effective and the project cost is reduced 14.89% when the reliability-based optimization design is used.

Abstract: The determining of m value in “m” method has great significance to force analysis of pile foundation buried segments. In this paper, a finite element software is used for the nonlinear finite element analysis of elastic long pile under the horizontal force action, and combined with the related provisions and formulas for “m” method given in 《Code for Pile Foundation of Harbour Engineering》, a accurate m value can be obtained conveniently. Then based on this method and by the single factor analysis, a more systematic study was made to the related factors, and obtained the influence law of various factors to m value.

Abstract: Foundation treated with dynamic compaction replacement method can not only improve the foundation strength but also improve the drainage condition, which is advantageous to the consolidation of soft soil. Compared with the widely used immersed tube piles, its construction time is shorter and the benefit is obvious. With a warehouse project as an example, this paper expounds the scheme design, parameter selection, test, inspection, etc. in soft soil foundation treatment in muddy geological conditions taking dynamic compaction replacement method.

Abstract: Beijing’s hutong and siheyuan buildings have a long history with hundreds of years.In the beginning,this article introduces the historical background of Beijing’s siheyuan,thus it can be seen that finding a more suitable development mode for beijing’s hutong buildings is extremly urgent. Then,throgh listing several transformation and renovation cases of famous hutong and siheyuan building,analyzes different development modes of reforming and renovation.By means of these analysis and comparision of the cases,the article is aimed at providing some guidance and references for similar buildings’ rebirth and blossom.

Abstract: Hollow cylinder torsional shear test is simulated regarded as a boundary value problem employing a three-dimensional static/dynamic soil-water coupled finite deformation analysis to investigate the influence of the specimen geometries on apparent behavior concerned in practical experiments. 1) A “Perfect path” which means the response of a single three-dimensional element with uniform deformation is calculated to investigate the effect of non-uniformities on the apparent behavior. As can be seen, only the apparent behavior with thinnest wall thickness coincides with the “Perfect path”, which indicates a uniform deformation inside the thinnest specimen; 2) It was found that when the cylinder wall thickness became smaller, the non-uniformity also decreased correspondingly, which can also be seen in the element behaviors of the thickest specimen; 3) Even thought the non-uniformity in different geometries is quite different, there seem to be no significant influence on the apparent behavior. The reason may lie in the extreme constraint conditions, namely displacement control.

Abstract: Ventilation system of highway tunnel is the key factors of keeping normal operations. In addition to the normal operation of keeping tunnel environment, the need to control the spread of smoke and meet requirements of escape and rescue work in fire case. This article describes the design guidelines of emergency ventilation system for different types of road tunnel. This article will help long highway tunnel ventilation system to improve the ability to deal with fire, improve operational safety.

Abstract: Peck method and Stochastic medium method (SMM) are widely used in the field of ground movement included by urban soft ground tunnelling in China. The determination for the key parameter for SMM is also a problem because of the relative little experience from the engineering application in China. Through discussing the theoretical relationship between Peck method and SMM, Peck method can be regarded as a simplification of SMM where is used in relatively deeper excavation condition, and the method of determination for the key parameter for SMM is suggested. The suggested method are proven and verified by some practical engineering projects. Finally, they can significantly improve the adaptability of SMM in engineering application.

Abstract: A laboratory model test of tunnel anchor was conducted to investigate its pullout mechanism and bearing capacity. Surface and rock deformation, strain and stress were measured during the entire model test process. The results show that: under pull out load, tensile failure first occurs in top surface rock near the anchor, then shear failure occurs in anchor-rock interface and rock around the anchor. The failure surface is inverted cone from the anchor bottom. Under 50 times design cable force tunnel rock is in elastic stage, suggesting that current tunnel anchor design is quite conservative and can be further optimized.