Abstract: Two dynamic numerical simulation models of horizontal bedded rocky slopes were established with Finite Element Analysis (FEA) according to the archetype of rock slope in “5.12” Wenchuan earthquake, and the simulation was validated with a shaking table model test. In the two models, one named A is the upper is hard and the bottom soft rock, and the other named B is the upper is soft rock while the bottom is hard. The result indicates that there exists amplification effect on elevation in both slopes under horizontal earthquake wave, the amplification factor of PGA in model A is larger than that in model B following the increase of the amplitude and the duration, and the slope displacement in model A is also larger than that of model B in the effect of the amplitude, frequency or duration. These show that model A is in disadvantageous compared to model B, and the stability destroy is produced easily in model A.
Abstract: It is reported that the impact factor is influenced by many parameters, whereas in most cases the impact factor is only related to the main span or the fundamental frequency of the bridge. In order to study the sensitive influence parameters of the impact factor for rigid-frame continuous combined bridge, based on the bridge-vehicle coupled vibration, nine influence parameters are considered ,which include the ratio fundamental frequency of vehicle to bridge, the mass of vehicle, the roughness of deck, the damping ratio of vehicle, the velocity of vehicle, the driving mode of vehicle, the rigidity of bridge, the arrangement of bridge and the soil-structure–interaction mode, then orthogonal test table is employed to study the structural impact factors in the critical sections under those parameters respectively, thus the sensitive parameters are derived. The results show that the ratio frequency of vehicle to bridge, the roughness of deck, the velocity of vehicle are the sensitive parameters affecting the impact factors. Therefore the impact factor should be interpreted as the function of muti-parameters rather than of only one parameter.
Abstract: It was presented for the results of 3D finite difference analysis on the behavior of single pile in clay. Firstly, it was discussed to the effect of model’s mesh fineness and soil parameters on pile response. And it was founded that the mesh size less than 0.2d (diameter of pile) was reasonable. In additions, when the soil was soft or the E(soil elastic modulus) was small, the effect E of on lateral capacity of pile was larger than the soil was stiff clay with soil elastic modulus increasing. Lastly, the results of the numerical simulation carried out in this study were compared with a published field lateral loading tests, a good correlation between the field test and the numerical simulation was obtained based on reasonable mesh size and material parameters.
Abstract: Through analysis of model test results, some of the basic sliding piles features of the frame anti-slide pile can be obtained. Under the thrust of landslide, a complex parabola and line function could be used to describe the relationship of load and lateral displacement of pile head. At the same time, there was a big crack in front of the pile. It was shown by monitoring the soil pressure that pushing force acting on the back frame pile was trapezoidal distribution and on the leading frame pile was parabola distribution. The soil pressure value was larger at back piles central and around sliding surface and smaller at the head of piles. the landslide thrust acting on the back piles more larger than the front row piles, the central of piles’ maximum soil pressure minimum 1:3 ratio of the middle pile at the before and after row, the ratio between the changes with the load. Frame pile of the inflection point after another figure appeared, at the top of the link beam and ring beam structure of the entire framework of the pile Showed a synergistic effect of spatial, compare to other forms of single row of piles and others forms, it can significantly reduce the size, to achieve the economic security landslide treatment goal, there is wide application prospect.
Abstract: In this paper, CT technique is applied to observe soft soil of different depth , and microstructure characters are analyzed combined with scanning electronic microscope (SEM) and mercury intrusion method. CT images comprehensively reflect the soil microstructure, while every voxel of CT image can be observed with SEM. CT images grey value can reflect the porosity variance, and grey value variance express homogeneity of soil microstructure
Abstract: The intensity and deformation characterization of a rock mass is an important input parameter in any analysis of rock mass behavior. Field tests to determine this parameter directly are time consuming, expensive and the reliability of the results of these tests is sometimes questionable. Consequently, several authors have proposed empirical relationships for estimating the value of an isotropic rock mass deformation modulus on the basis of classification schemes. But the result is different by different people. Therefore, A new approaches to the mechanical characterization of jointed rock masses has been studied based on the test of little rock mass sample. But preparation of jointed rock mass samples in site is very difficult. In this paper, a method for collecting, preparing and describing samples with extremely to very closely spaced fractures is described where no cementing material is required.
Abstract: Based on the investigation and analysis of acid sewage quality component in some metal mine, and combining with the investigation on the engineering geology and the character of similar soil slope, the interaction and corrosion mechanism are studied between acid mine drainage and similar soil slope, it shows that the AMD changes the microstructure of rock-soil, displace and dissolve the integrant, magnify the structural scale, and hasten the new rift. The reinforcing treatments are proposed about using vetiver to consolidate the slope. The result from the practice shows that it has perfect mechanical effect using veriver to protect slope, and it is available to protect the similar soil slope, reduce the slope erosion-damage, and improve the slope stability.
Abstract: This paper aims at the incompatibility of indices in comprehensive evaluation of supporting scheme for foundation pit. An optimization model based on extension sets is presented. The model takes the scheme to be evaluated, evaluating indices and its characteristic value as matter elements, relational function are constructed according to the expertise and practice and optimum scheme is obtained by calculating the comprehensive relational degree. Compared it with fuzzy optimization theory model, the results achieved is consistent coincident.
Abstract: Loess has been subjected to long-term deposit, geological structure and weathering under the condition of self-weight and above covered load. Accordingly, it would result in many vertical joints and differences in mechanical response and deformation properties for vertical and transverse. In order to obtain different mechanical properties of vertical and transverse, laboratory physical mechanics tests (collapsible test, consolidation test, direct shear test, triaxial compression test and unloading test) were carried out to investigate typical Q3 loess from field above He Jia-zhuang tunnel of Huang Tu-liang district on Zhengzhou-Xi’ an high-speed passenger rail line in China. The results suggest obvious anisotropic properties of undisturbed loess. Not only do the conclusions supply theoretical foundation for design and construction of tunnel in loess, but also can act as guiding reference for similar underground engineering.
Abstract: During the design of foundation of a high-rise building with large space requirement at the ground floor, CFG piles are used in substitution for cast-in-place piles. By advanced design and construction, the project was completed successfully. In this paper, the experience was introduced according to the procedure of actual construction.