Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province

Lanzhou, China

Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province

Lanzhou, China
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Wang Q.-C.,Lanzhou Jiaotong University | Wang Q.-C.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Zhang R.-L.,Lanzhou Jiaotong University | Zhang R.-L.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province
Tiedao Xuebao/Journal of the China Railway Society | Year: 2011

The treatment of loess roadbed disease on raising speed railway had important significance for road safety. The experimental research on indoor simulation test about existing lines loess roadbed disease. Forming reason, mechanism, experience stage of slurry vein and soil displacement in different pressure grouting, slurry vein trend have been investigated, fitting formula was obtained. Theoretical analysis was proved by test device. The experimental results indicate that the second splitting can hardly occurred in collapsibility loess roadbed with 0.3 MPa~0.5 MPa pressure. filling effect, extrusion effect, frame effect played a main role in fracturing grouting; the role of fine slurry cannot be neglected in forming slurry pipeline by surrounding soil; the slurry vein is openning fracture.


Li Z.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Li Z.,Lanzhou Jiaotong University | Fan Y.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province
Advanced Materials Research | Year: 2012

Based on the research of CFRP reinforced concrete beam, this article indicates that CFRP can improve greatly the fatigue performance of damage concrete beam, prolong its service life, and provide the experimental basis for long-term fatigue properties of CFRP concrete structures.


Zhang Y.-L.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Zhang Y.-L.,Lanzhou Jiaotong University
Advanced Materials Research | Year: 2012

Based on mechanical properties of railway extradosed cable-stayed bridge with the rigid continuous beam system in the high-intensity earthquake zone, three kinds of scheme on seismic response reduction including viscous dampers, lock-up device and friction sliding bearings is presented in the text and effectiveness of seismic response reduction is analyzed by using non-linear time history response analysis. The results show that three types of isolation devices are significantly effective for improving seismic performance of the railway extradosed cable-stayed bridge. Seismic response reduction of viscous damper and Lock-up device is better, that of friction sliding bearing is second. but the type of viscous dampers is most optimal considering from normal use for structure and distribution of the seismic response in the structural system.


Liang Q.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Liang Q.,Lanzhou Jiaotong University | Liang Q.,Khan Research Laboratories | Li J.,Khan Research Laboratories | And 4 more authors.
Rock Mechanics and Rock Engineering | Year: 2013

The vibrations of existing service tunnels induced by blast-excavation of adjacent tunnels have attracted much attention from both academics and engineers during recent decades in China. The blasting vibration velocity (BVV) is the most widely used controlling index for in situ monitoring and safety assessment of existing lining structures. Although numerous in situ tests and simulations had been carried out to investigate blast-induced vibrations of existing tunnels due to excavation of new tunnels (mostly by bench excavation method), research on the overall dynamical response of existing service tunnels in terms of not only BVV but also stress/strain seemed limited for new tunnels excavated by the full-section blasting method. In this paper, the impacts of blast-induced vibrations from a new tunnel on an existing railway tunnel in Xinjiang, China were comprehensively investigated by using laboratory tests, in situ monitoring and numerical simulations. The measured data from laboratory tests and in situ monitoring were used to determine the parameters needed for numerical simulations, and were compared with the calculated results. Based on the results from in situ monitoring and numerical simulations, which were consistent with each other, the original blasting design and corresponding parameters were adjusted to reduce the maximum BVV, which proved to be effective and safe. The effect of both the static stress before blasting vibrations and the dynamic stress induced by blasting on the total stresses in the existing tunnel lining is also discussed. The methods and related results presented could be applied in projects with similar ground and distance between old and new tunnels if the new tunnel is to be excavated by the full-section blasting method. © 2012 Springer-Verlag.


Chen Z.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Chen Z.,Lanzhou Jiaotong University | Zhao D.,Lanzhou Jiaotong University | Zhao D.,Northwest University for Nationalities | And 3 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2011

With Guanjiao tunnel as engineering background, the model for calculating the release ratio of excavation stress was adopted to study the lining pressure of railway tunnel under the geological conditions of high geostress and soft surrounding rock. Based on the in-situ measured geostress and construction monitoring displacement, the displacement around the tunnel unable to be monitored and the displacement before tunnel face were calculated according to the space effect in the excavation by benching tunneling method. Then, the final displacement of tunnel surrounding rock was forecasted by the improved BP artificial neural network model. The tunnel lining pressure and stress release rules were obtained by using the model for calculating the release ratio of excavation stress. The rules obtained by the above methods are generally consistent with the characteristic curves of classic surrounding rock and basically correspond with engineering experience and the state of site construction. The correctness and rationality of the above method under the geological conditions of high geostress and soft surrounding rock are validated by 3D numerical simulation using FLAC3D software. Both the calculation and simulation results indicate that the lining pressure at DyK307+900 is greater and the stress of the tunnel structure is in an unfavorable state because of the high geostress, soft surrounding rock and insufficient primary lining effect.


Jinxuejun,Lanzhou Jiaotong University | Wanggenhui,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province
Open Mechanical Engineering Journal | Year: 2015

Nonlinear hysteresis characteristics are usually used in the elastic-plastic seismic analysis of the structure of bridge. These characteristics may be described by the relationship of section bending moment and curvature. This relationship can be obtained by the section size and reinforcement, which is also a simple and timesaving method to evaluate the seismic behavior of the section. The thesis made a research of the effect of section bending moment and curvature first. Then chose five different sections and observed their effects on bending moment and curvature. The results indicated that, with the increasing of section size, the crack, the yield, the moment damage and the curvature of the section are increased. The increasing of section size is that the increasing of moment of inertia, so with the increasing of the moment of inertia, the resistance to crack, field and damage of the bridge pier is stronger. On the basis of this, the elastic-plastic time history analysis of Wu Guan super highway Gan Gou Zi Bridge is made. It showed that the capacity of energy dissipation by hysteretic of the Rectangular thin-wall pier is better than the twin shaft pier. So it is best to use rectangular thin-wall pier in the same condition. © Jinxuejun and Wanggenhui;.


Wei Z.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Wei Z.,Lanzhou Jiaotong University | Zhang Y.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Zhang Y.,Lanzhou Jiaotong University | And 2 more authors.
Advanced Materials Research | Year: 2012

The static load test of composite foundation was simulated by using the nonlinear finite element programs, and the changes of the pile-soil stress ratio and the pile and soil settlements as well as the plastic deformation of composite foundation were analyzed. The simulation results show that: the cushion of flexible pile composite foundation can effectively regulate the pile-soil stress ratio and make the bearing capacity of the lime soil pile and the soil between piles give full play at the same time. The cushion has a distinct role in reducing the pile settlements, however, has little effect in reducing the soil settlements. The reasonable cushion thickness is about 300mm. The composite foundation will emerge local shear failure when it reaches the ultimate bearing capacity. Reducing the pile spacing can increase the ultimate bearing capacity, and the rate of increase shows a gradually increasing trend. © (2012) Trans Tech Publications, Switzerland.


Chen Z.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Chen Z.,Lanzhou Jiaotong University | Zhao D.-A.,Lanzhou Jiaotong University | Zhao D.-A.,Northwest University for Nationalities
Advanced Materials Research | Year: 2011

The substantial difficulties are encountered as the huge computation of complex three-dimensional finite element model. Network parallel computing is one of the most compelling topics at the forefront in the current field of parallel computing, the size and the speed of structural analysis can be increased by the combination of both, so that large and complex three-dimensional finite element calculation can be carried out smoothly. According to Wushaoling tunnel, three-dimensional finite element model is established and implement under the support of the finite element parallel computing environment of Deep Comp 1800 cluster system based on the analysis of neural network. The realization of 3D geostress analysis is also depend on the artificial neural network computation program ANNBP and MEBAC, which is an interface program connecting ANNBP and ANSYS. The results show that the computation efficiency is highly improved by the Deep Comp 1800cluster system, the distribution of the initial geostress field is compacted significantly by the faults and there is a vertical extrusion characteristic with the tunnel at the fault zone. © (2011) Trans Tech Publications.


Yu Y.-Y.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Yu Y.-Y.,Lanzhou Jiaotong University | Yu L.-F.,Xian Railway Bureau
Jisuan Lixue Xuebao/Chinese Journal of Computational Mechanics | Year: 2010

Based on the method of reverberation-ray matrix, the velocity mobility, at the top of defective pile with variable sections embedded partially in homogeneous soil, under unit exciting force, is derived. The time velocity response at pile top is further obtained by inverse Fourier transform and convolution theorem acted by a half-sine impulse. The velocity mobility and reflecting waves of the neck-reduced pile, neck-expanded pile, and perfect pile embedded partially in homogeneous soil are compared. The effect of defective type, defective length, defective location and defective degree on velocity mobility and reflecting wave at the pile top are further analyzed, and the velocity mobility curves and reflecting wave curves of neck-reduced-expanded pile and neck-expanded-reduced pile embedded partially in soil are compared. It is shown that the influence of the medium change around the pile to mobility curves and reflecting wave curves is less than that of the defect of pile.


Zhang Y.,Lanzhou Jiaotong University | Zhang Y.,Key Laboratory of Road and Bridge and Underground Engineering of Gansu Province | Wang X.,Lanzhou Jiaotong University | Liang Q.,Lanzhou Jiaotong University | And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

The model test material of collapsible loess is the bottleneck of similar materials model research in geomechanics, which has limited the application of model tests in loess area. A model test material for collapsible loess is successfully developed after a lot of compounding tests by airfall method. This similar material is firstly mixed with barite powder and sand as non-cohesive material, and industrial salt, gypsum and bentonite as cohesive material. Then the material is mixed with water evenly. After wetted for 24 hours, the samples are produced by airfall method. At last, the samples are maintained at constant temperature of 50°C, which simulates the deposition mode and formation conditions of eolian loess, to obtain the targeted model test material. Odometer collapse test results show that this artificial material have similar collapsibility with natural loess; and also produce significant collapse when wetted. Shear test results indicate that shear strength parameters of the similar material are much close to natural loess. Since the density of the similar material can be adjusted widely, the model test material developed by the above method would be an ideal model test material for collapsible loess.

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