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1.
Hiroshi Kobayashi Keiichi Tamura Shunsuke Tanimoto 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):1135-1141
In order to improve seismic design technology of bridges, it is necessary to evaluate the vibration characteristics of a bridge–soil system that consists of soil, foundation structure, pier and superstructure. However, there have been few experimental studies on seismic behavior of bridge–soil system. In this paper, we conducted the hybrid vibration experiment on seismic behavior of bridge–soil system, and examined the applicability of hybrid vibration experiment to study seismic response of bridge–soil system. Based on the experiment results, seismic response of bridge was quantitatively studied. 相似文献
2.
Zhao-Dong Xu Ya-Peng Shen Hong-Tie Zhao 《Soil Dynamics and Earthquake Engineering》2003,23(8):683-689
The paper introduces a synthetic optimization analysis method of structures with viscoelastic (VE) dampers, namely the simplex method. The optimal parameters and location of VE dampers can be determined by this method. Numerical example and a shaking table test about reinforced concrete structures with VE dampers show that the seismic responses of structures will be reduced more effectively when the parameters and location of VE dampers are designed in accordance with the results calculated by the simplex method. 相似文献
3.
Earthquake-induced slope stability is evaluated by the force-equilibrium method in engineering practice. This method provides a safety factor against initiating failure or displacement according to the Newmark model along a fixed slip surface but it cannot evaluate failure deformations after failure occurs. An energy approach is proposed as an alternative means for evaluating slope failures and subsequent flow deformations. The driving energy for slope displacement is considered to be the earthquake energy and the gravitational potential energy. As a first step in the research, an energy balance is formulated for the model of a rigid block resting on an inclined plane. Then, an innovative model test is developed, in which the energy balance in a sliding slope is measured on a shake table. The earthquake energy used for the slope failure can be successfully quantified in the test and its contribution to displacement is discussed in the light of the energy balance established for the block model. 相似文献
4.
本文分析了广州市某２８层高层建筑模型模拟地震振动台试验结果,对此建筑的抗震性能进行了评价,考究了设置摩擦耗能支对其动力反应的减震作用。 相似文献
5.
The role of the seismic soil–pile–structure interaction (SSPSI) is usually considered beneficial to the structural system under seismic loading since it lengthens the lateral fundamental period and leads to higher damping of the system in comparison with the fixed-base assumption. Lessons learned from recent earthquakes show that fixed-base assumption could be misleading, and neglecting the influence of SSPSI could lead to unsafe design particularly for structures founded on soft soils. In this study, in order to better understand the SSPSI phenomena, a series of shaking table tests have been conducted for three different cases, namely: (i) fixed-base structure representing the situation excluding the soil–structure interaction; (ii) structure supported by shallow foundation on soft soil; and (iii) structure supported by floating (frictional) pile foundation in soft soil. A laminar soil container has been designed and constructed to simulate the free field soil response by minimising boundary effects during shaking table tests. In addition, a fully nonlinear three dimensional numerical model employing FLAC3D has been adopted to perform time-history analysis on the mentioned three cases. The numerical model adopts hysteretic damping algorithm representing the variation of the shear modulus and damping ratio of the soil with the cyclic shear strain capturing the energy absorbing characteristics of the soil. Results are presented in terms of the structural response parameters most significant for the damage such as foundation rocking, base shear, floor deformation, and inter-storey drifts. Comparison of the numerical predictions and the experimental data shows a good agreement confirming the reliability of the numerical model. Both experimental and numerical results indicate that soil–structure interaction amplifies the lateral deflections and inter-storey drifts of the structures supported by floating pile foundations in comparison to the fixed base structures. However, the floating pile foundations contribute to the reduction in the lateral displacements in comparison to the shallow foundation case, due to the reduced rocking components. 相似文献
6.
《地震研究进展（英文）》2021,1(3):100031
In order to study the overall deformation of geotechnical model conveniently, the worksite of landslide bridge foundation reinforced by the front and rear row anti-slide piles in Chenglan railway was taken as an example. On the basis of shaking tabe test of a 1/40 reduced scale model, the landslide deformation caused by vibration waves was monitored through burying self-made phosphor bronze strips in soil. Combined with the horizontal and vertical coordinates of the bending strain points on the phosphor bronze strips, the digital matrix was converted by applying Renka Cline random matrix generation method, and the two-dimensional contour plots were drawn based on it. The results showed that the two-dimensional contour plots reflected the basic law of landslide deformation reasonably, and it revealed the evolution process of landslide deformation and failure. The research conclusions were consistent with the test phenomenon, which met the basic requirements of overall deformation analysis of landslide model. This proposed method can monitor multiple cross sections and was practical for model test. 相似文献
7.
A crucial aspect of physical geotechnical model tests (under both 1-g and n-g conditions) is the evaluation of the initial (low-strain) stiffness of the soil layers of the sample test deposit, especially in the case of coarse materials. While for uniform soil deposits this issue can be addressed in a straightforward manner, e.g. by determining the fundamental frequency through the transfer function of an applied white-noise excitation, the problem becomes cumbersome for multi-layered deposits. After reviewing a number of available theoretical solutions, this paper illustrates a simplified yet reliable analytical procedure for determining the shear wave velocity profile (Vs) in a single or bi-layer deposit, taking into account the inhomogeneity of the individual soil layers, under the hypothesis of vanishing shear modulus at ground surface. The fundamental natural frequency of the inhomogeneous bi-layer deposit is analysed using the Rayleigh quotient procedure. The associated shape function is evaluated by considering the equilibrium of the soil column under a pseudo-static lateral inertial excitation imposed at its base, accounting for both layering and inhomogeneity. A validation of the proposed method is provided by comparing numerical results obtained from both time- and frequency- domain analyses against experimental data on Leighton Buzzard sand, from a recently-completed research project conducted on the shaking table facility at BLADE Laboratory, University of Bristol (UK). 相似文献
8.
Shaking table tests were performed to investigate the damage mechanisms of a subway structure in soft soil while experiencing strong ground motions. The seismic responses of the structure and soil were found to be more sensitive to input motions with richer low-frequency components. The excess pore pressure ratio of soil increased slightly, and the distribution of the excess pore pressure surrounding the structure showed clear spatial effects. The frequency spectrum characteristics of input ground motions clearly influenced the lateral displacement of the structure. In addition, the structure was most severely damaged at the top or the bottom of the interior columns. Finite element analyses were conducted by using the modified Martin–Seed–Davidenkov viscoelastic and the rate-independent plastic-damage constitutive models for soil and concrete, respectively. Satisfactory agreement was observed between the simulation and test results, the difference between these results was discussed in detail. The results provide insight into how the characteristics of strong ground motion might influence and present a simplified analysis method to quantitatively evaluate the damage of subway structures in soft soil. 相似文献
9.
Seismic performance of natural slopes, earth structures and solid-waste landfills can be evaluated through displacement-based methods in which permanent displacements induced by earthquake loading are assumed to progressively develop along the critical sliding surface as a result of transient activation of plastic mechanisms within the soil mass. For sliding mechanisms of general shape the earthquake-induced displacements should be computed using a model that provides a closer approximation of sliding surface. When large permanent displacement are induced by seismic actions, due to substantial shear strength reduction, and significant changes in ground surface occur, an improved estimate of permanent displacement can be obtained using a model which accounts for shear strength reduction and mass transfer between adjacent portions of the slope resulting from geometry changes of ground surface during the seismic event.In this paper, a GLE-based model is proposed for seismic displacement analysis of slopes that accounts for shear strength degradation and for geometry rearrangement. Model accuracy is validated against experimental results obtained from shaking table tests carried out on small scale model slopes. Comparison of computed and experimental results demonstrates the capability of the proposed approach in capturing the main features of the observed seismic response of the model slopes. 相似文献
10.
Fiber reinforced soil behaves as a composite material in which fibers of relatively high tensile strength are embedded in a matrix of soil. Shear stresses in the soil mobilize tensile resistance in the fibers, which in turn imparts greater strength to the soil. In this paper a study on the influence of synthetic fibrous materials in improving the dynamic response characteristics of fine sandy soil is reported. The project aims at converting fibrous carpet waste into a value-added product for soil reinforcement. A series of five shaking table tests using rigid box were carried out on Toyoura sand specimens reinforced with randomly distributed geotextile strips. The dynamic deformation characteristics of the reinforced sand are defined in terms of wall lateral deformation and rotation. The results clearly indicate the effectiveness of fiber reinforcement in improving dynamic properties of fine sand and deformation characteristics of fiber reinforced sheet pile retaining wall during shaking. 相似文献