Advanced Materials Research Vols. 639-640

Abstract: Based on the reinforcing mechanism of dynamic replacement method ,this article put forward the construction parameters and measures of dynamic replacement method , combining with the result of actual engineering field testing experiment. The field load test, standard penetration test and pore water pressure test results show that the characteristic value of subgrade bearing capacity is more than 130 kpa when the tailings residue subgrade has been managed with dynamic replacement method, providing references for applied research on dynamic replacement method in tailings residue subgrade reinforcement.

Abstract: On the basis of summing up the characteristics of water level and the channel where the bridge is located of Huanghuayuan Jialing River Bridge of Chongqing City, the risk of ship collision and structural characteristics were analyzed with the advanced risk analysis methods of AASHTO method and integral path methods with three probability parameters. The pier protection measures raised on this basis include that P1 pier is designed with anti collision pier and in the design of P2 pier, the floating anti collision box programs based on the highest water level and the anti collision pier program are raised and a comparatively studied. These conclusions provide some references for the anti collision design of bridges under similar environments.

Abstract: The disasters in mountainous cities are serious and special, which have wide distribution range and whose relative factors are fuzzy and complicated. So, in mountainous industrial cities it should pay more attention to prevent and reduce disasters especially. The article takes mountainous city Changshou District of Chongqing as an example, which is also the typical heavy chemical industrial city, to discuss the planning strategies of preventing and reducing disasters for heavy chemical industrial city in the complex mountainous topographical conditions.

Abstract: The purpose of the this study was to find the influence of local members of high-rise reinforced concrete frame-shear wall structure failed in different position.Referred to the basic requirements against progressive collapse provided by JGJ03-2010,Based on alternate path method ,This paper presents an analysis procedure that made Linear static analysis to a modal of 24-storey frame-shear wall structure designed according to the current code with SAP2000.The results show that once the edge column failed ,the structure will collapse.However,the corner shear wall constitute little threat to the progressive collapse.After the local members failed ,the lower part of the building contribute to the load path and it can results in axial force ruleless in beams,which make against to load bearing if they are tensile forces.The concentrated tensile stress appears around the continuous beam,and it is possible to be broken early after local member failed if close to the failed shear wall.

Abstract: The shield tunneling construction would cause the buried pipeline deformation. In order to predict the influence to the buried pipeline when shield tunneling crossing the thick and hard strata, taking 201 contract section shield tunneling of Dalian Metro construction as the research object, the buried pipeline deformation effects are analyzed. Firstly, the shield tunnel excavation and support simulating model is constructed basing on Flac3D technique. Secondly, the ground settlement and its influence to the buried pipeline are analyzed with finite difference digital computation. According to the simulation for the shield tunneling crossing the thick and hard riverbed, the settling volume of the ground, the deformation modes and degrees of the buried pipelines are discussed to reveal the deformation rules. Results show that the deformations of two groups of measuring points tend to be uniform; the excavation process includes the stabilization period, the critical point and the deformation period in 50m long simulation model; the drainpipe appears deformation from three directions, and the severity of deformation mainly comes from the vertical direction settlement.

Abstract: According to the instance of turnover and twist of conductor-spacers system,a question of torsional stability of conductor-spacers system is proposed.The paper analyzes the reason why the torsional instability of the entire system occurs and puts forward that the residual torque moment has existed during the process of conductor stranding,which creates a security risk to the stability of the system.In addition,the torque moment caused by the uneven ice-covering and different periods of ice-shedding will leave the system unbalanced.Finally, methods of improving the stability of conductor-spacers system is discussed.

Abstract: Because of the local crack and seepage, a double curvature arch dam of concrete block in Jiangxi Province was urgently needed to strengthen, and the construction period was limited seriously. In order to solve the problem of drainage, a diversion tunnel about 24m must get throng in two weeks, and it is proved that the blasting excavation scheme is the only choice. Meanwhile, monitoring measurement must be taken to ensure the dam’s safety. In this article, the optimization design of blasting excavation and a vibration monitoring are completed and carried out respectively. Theoretical calculations and monitoring results showed that, those design schemes are scientific and rational, and disadvantageous effect of blasting vibration is under the control fully.

Abstract: With the rapid development of economy, highway infrastructure is gradually extended to desert region. But at present, affected by the special engineering geological environment in desert areas, the work must be majorly planned and considered before the highway project is set that how to reduce the construction cost while ensuring the desert highway construction quality, and maximizing the maintainance and further improvement of desert environment. The wind and sand environment characteristic of desert areas is analyzed in this paper, then the common types of desert highway subgrade slope are investigated and the stability of wind-blown sand subgrade slope is studied, finally the theories and methods according to the characteristics of the desert subgrade are proposed.

Abstract: This dissertation mainly analyzes that the deep foundation pit engineering in civil construction, which may impact on the environment and could cause disasters. Dealing with the deep foundation pit engineering to the control ofinternal process and harmony of exterior environment system research, which puts forwards the corresponding measures to conserve the environment.

Abstract: Bayesian theory is adopted in modal parameter identification, finite element model updating and residual capacity evaluation of the structures recently. Fast Bayesian FFT modal identification approach provides a rigorous way to obtain modal parameters and well-separated modes using the fast Fourier transform under ambient excitation. Moreover, it avoids choosing the modal order or removing false modes based on the stable diagram and has its obvious advantages. In this paper, modal parameters of a rigid frame-continuous girders bridge under ambient excitation are identified by this approach. Comparison with stochastic subspace identification (SSI) method indicates that Fast Bayesian FFT is a good approach to identify the modal parameters even for a large number of measurement channels.