共查询到20条相似文献，搜索用时 46 毫秒
1.
The influence of blasting vibration on the adjacent buildings is inevitable if blasting is employed for excavation. Daping station tunnel of Chongqing light railway project, on which there is dense with population and buildings, has a minimum buried depth of only four meters and maximum span length of 26.3 meters. The stepped excavation mode with short hole, multi round and V shaped cut are adopted. The maximum charge weight of one delayed interval is determined by the permitted vibration velocity. The smooth blasting technology with adding vibration reduction holes is used. Meanwhile, the charge weight per hole is strictly controlled. With the simulation and on site test, it is found that the proposed technology for tunnel construction is feasible. 相似文献
2.
Wind induced vibration is one of the main control factors in the Long span bridge structure design. The wind tunnel tests for measuring the static wind forces on the bridge girder and the section model wind tunnel dynamic testing for Caiyuanba Yangtze River Bridge in Chongqing are introduced in this paper. The wind tunnel testing for measuring static wind forces and vortex- induced vibration test on the arch are introduced taking account of the influence between two arches. The main contents and outcomes of testing are presented. It is indicated that the bridge girder has excellent wind stability and the arch mechanical characters are rather complicated. The drag force on the hind arch varied a lot because of the font arch interference on the wind flow. The drag force on the hind arch will be negative when two arches are close to each other. It increases with the space of two arches. The results of testing will give the data of buffeting and vortex - induced vibration and flutter analysis of the bridge. 相似文献
3.
According to the measurement during excavation of Jinzhou tunnel with four lanes in one cave which lies on the rebuilt highway from Shenyang to Dalian, this paper analyzes the rock deformation rule, discusses the reason of instability after a highway tunnel was excavated, emphasizes the necessity of the construction stability monitor and active control. The importance of support is Fresented with bolts and shotcrete to improve and enhance the carrying capability of the rock. It is necessary to insist on the rule of measurement and active control to ensure the safety and quality of tunnel construction. 相似文献
4.
In process of the tunnel construction throw New Austrian Tunnelling Method, the result of smoothwall blasting to rock tunnel is not good, there are more and more cavities produced behind the lining. On the basis of engineering project, this paper makes the three-dimensional elastic-plastic analysis throw numerical simulation, discusses the stress-strain behavior of primary support when there is a different size of rectangle cavity behind the lining. In addition the safety factor of tunnel is calculated with cavity based on the strength reduction finit element method. This factor is compared with the factor of health tunnel. The stability of tunnel structure system is estimated through the linear regression analysis between stress of lining and safety factor. 相似文献
5.
WANG Ke zhong 《保鲜与加工》2008,(5):42-46
Based on the large scale conceptual model theory of similar material, a physical model of metro station tunnel excavation was simulated. The excavation process of metro station tunnel between existing double tubes also was simulated. Ground settling, soil deformation and displacement of specific points around tunnels were studied. The influence of a cast in place pile on reducing soil displacement was simulated. The dynamic mechanical behavior and deformation laws of the soil were obtained along with some useful conclusions. The conclusions are beneficial for guiding the construction and expanded excavation of metro station spaces between existing double tubes. 相似文献
6.
Calculation of Influence on Longitudinal Deformation of Adjacent Tunnels Due to Excavation 总被引：1，自引：0，他引：1
Unloading of excavation of foundation pit has influence on adjacent tunnels, therefore it is important to predict the deformation of metro tunnels to ensure the operation of tunnel. The displacement effect due to the surrounding wall soil unloading of adjacent excavation was not considered by the theoretical analysis method, and the analysis procedure of FEM was usually too complicated to get a satisfied result, so the horizontal and vertical additional stress were calculated by the Mindlin solutions. Furthermore, the tunnel structure was considered as the beam with infinite length. The additional stress was imposed on the Winkler model and the governing equation was built up on the adjacent tunnel structure. Finally, displacements and internal forces of existing tunnels were obtained. Compared with the numerical simulation and an engineering case, the results of the presented formula are in good agreement. It can provide certain theoretical and calculation basis for metro tunnels influenced by adjacent excavation. 相似文献
7.
Recently, the construction of neighboring highway tunnels with small interval gets more and more in China. The construction of such tunnels proceeds usually by excavating one after another. The second tunnel is constructed with the surrounding rock disturbed by the first one. And the construction of second tunnel also has effect on the first excavated one. For revealing the interaction laws of such tunnel construction in combination with the engineering practice of Lanfeng tunnel at Jinshan Road in Chongqing, The FE numerical simulation analysis was used to study the characters of surrounding rock deformation, stress field, and plastic zone of the tunnel. From this analysis, it clearly shows that the excavation of second tunnel has significant influence on the first one. This study provides a scientific basis for design and excavation of neighboring highway tunnels. 相似文献
8.
The fact of tunnel smooth blasting is those reduce over break and minimize fracturing of the rock at the boundary of an excavation. The select ruler and assured method of smooth blasting parameter are discussed, and the quality check standard of the smooth blasting, based on the under and over-break (5~15 mm), the circumferential hole mark ratio (>50%) and rock fragment, are found. A good benefit is gotten as these used in one tunnel. 相似文献
9.
以重庆东水门大桥—千厮门大桥渝中区连接隧道为研究对象,基于UDEC软件建立离散元数值模拟分析模型,研究了城区连拱隧道施工引起的地表沉降,上部建筑物基础沉降及倾斜,新建隧道下方已有轨道六号线的变形、受力特征,并将监测数据与数值模拟进行对比分析。结果表明,连拱隧道左侧隧道上导坑施工引起的隧道拱顶沉降和基础沉降量最大,经计算上部建筑物基础最大沉降量为3.81 mm,最大倾斜量为0.02%,建筑物基础沉降量和倾斜在规范许可范围之内;隧道施工引起的地层损失使得轨道六号线左拱肩向上隆起,六号线弯矩分布规律和其变形形态基本一致,弯矩最大值位于左拱肩部位,最大值为238 kN·m;数值模拟计算结果与监测数据量值相当,变形趋势基本一致;采用UDEC软件可以准确地计算出隧道开挖过程中节理的存在对隧道周围建筑物变形的影响。 相似文献
10.
Zhang LiangLiang Song XiaoBin Wu YunFang Zhu ZhengGang Xiao KeJian Lin GuanMing Lin RongSheng 《保鲜与加工》2005,(4):52
Considering the complication of the coefficient of wind-induced vibration for tall buildings,the scale 1:300 model test of Ying Li Building is completed in the second wind tunnel of Beijing University.Based on the calculation and analysis of the test results,the static and dynamic wind pressure acting on the building can be obtained and the value of the coefficient of wind-induced vibration for this tall building can be solved directly,thus a new way is laid for the research of complicated tall buildings. 相似文献
11.
YU Yong qiang QIU Xian de WANG Xin fei ZHANG Yong wu DU Xiao ping LIU Liang HE Yong cai 《保鲜与加工》2002,(10):105-109
A seismic effect is main harm in engineering blasting. By analyzing Seismic velocity and frequency of the main control factors of them, according to the data measured on the spot, the relation formula among Seismic velocity and dynamite and the distance between blasting fountain are obtained. Effects on buildings produced by vibration frequency and differences between blasting earthquake and natively seismic are analyzed. The calculation of blasting safety distance and selecting standard of breakage judge are studied and validated. The results of experiment and research indicate that we should attach importance to blasting seismic rules and effects on different buildings in order that basting techniques bring much economy benefits and reduce harm of blasting vibration as possible as much. 相似文献
12.
Aimed at the problem of the in partial section of the Nanjing Metro Line 3, the three-dimensional pattern of tunnel, segment and pile foundation was established after appropriate simplification. The simulation results showed that, the Overpass pile foundation of Shield Tunneling to Adjacent Metro Shield Tunnel will have effect on the force and deformation of the earth's surface and pile foundation, the maximum deformation value of the earth's surface is larger than that of the pile foundation top, stress concentration appeared in right working slope lower side segment of tunnel. Through the comparison with field monitoring results, the field dates is consistent with the Numerical Simulation Results, the execution parameters are advised to be well controlled in the further construction, in the same time strengthing the track monitoring, tracking grouting reinforcement should be carried when necessary. The research results could provide reference for the smooth going of the project. 相似文献
13.
Tunnel portal section mostly faces unfavorable geologic and topographical conditions, such as broken surrounding rock, shallow and unsymmetrical loadings. The current Chinese code for design of road tunnel provides the load calculation method of tunnel under unsymmetrical. However, according to the mechanic and deformation characteristics of the tunnel lining on site, the assumption is not suitable for the shallow tunnel under unsymmetrical loadings in broken surrounding rock. Therefore, through engineering case analysis and results of three-dimensional numerical analysis, the failure mechanism of shallow tunnel under unsymmetrical loadings in broken surrounding rock is presented firstly, that is, deep buried side broken surrounding rocks slump down after excavation and squeeze the lining, which makes the lining deform outward and bear passive earth pressure. Through the failure mechanism, the surrounding rock mainly includes slumping area and passive area. Then the corresponding formulas are deduced based on limit equilibrium theory. Finally, a case study is adopted to verify the feasibility of the new method. It is show that the new method is more reasonable than the method of current code. 相似文献
14.
Elastic-Perfectly Plastic Solution of Tunnel Surrounding Rocks Using Mogi-Coulomb Strength Criterion
Lyu Caizhong 《保鲜与加工》2014,(6):54-59
Reasonable choice of rock strength criteria is crucial for stress and displacement prediction and support design in tunnel engineering. Based on Mogi-Coulomb strength criterion and elastic-perfectly plastic model, analytical solutions of stress and displacement for surrounding rocks around a circular tunnel were derived The intermediate principal stress coefficient was used to present the intermediate principal stress effect. The results in this study were compared with the current solutions in the literatures and the influence of intermediate principal stress and shear strength parameters of surrounding rocks was discussed. The results showed extensive applicability and the Mohr-Coulomb strength criterion and Matsuoka-Nakai criterion are two special cases; when the intermediate principal stress coefficient b was equals to 0.5, the results indicated that the intermediate principal stress effect and its range for rock strength; the influence of cohesion and internal friction angle on the plastic radius and tunnel wall displacement was significant; Care should be taken to the effects of intermediate principal stress and shear strength parameter variations of surrounding rocks on tunnel design and construction. 相似文献
15.
Creep characters of tunnel supports structure is analyzed according to triaxial creep test of concrete specimen of deep tunnel supports structure adopting MTS815 hydraulic servo system. The creep parameters of nonlinear creep model are presented based oncreep curve. The finite element numerical model has been established considering tunnel construction process, creep characters of surrounding rock and support structure. The displacement characteristics, the effective stress and the maximum shear stress in different position in primary support and second lining are obtained through creep characters analysis of surrounding rock and supports structure. The features of displacement and stress dependent time of tunnel supports has visible difference comparing with discard creep effect and calculation displacement and practical monitoring results is basic concordance. The creep characters of surrounding rock and tunnel supports should be considered for deep tunnel. 相似文献
16.
Based on the elastic theory, an analysis can be made on stress and plastic deformation under tunnel excavation and shotcrete support.FLAC 3D can be used to simulate the mechanical behavior of excavation and support, getting the deformation of surrounding rock stress and plastic without support and shotcrete. The results show that, the prestress applied on the anchor equals to the supporting force when the tunnel plastic zone disappears. This support improves the self bearing capacity of surrounding rock, effectively suppresses the expansion of the plastic zone after the tunnel excavation, and prevents further damage to the tunnel surrounding rock. 相似文献
17.
Based According to the on the careful investigation in site of highway tunnel, the classification of tunnel disease is obtained. , design and construction of tunnel, in relation to the distribution of stress and loading of tunnel by numerical analysis and back analysis, the existing condition and reasons of tunnel diseases are carefully analyzed. At the same time, the disease management methods are provided, which are important to guide similar tur/nel to search diseases reasons and manage diseases. 相似文献
18.
As an example, through analyses of in situ measurements of Jinyun Road Tunnel and considering the geological environment and construction technics synthetically, relation among rockmass displacement and geological tectonics, rockmass sort, horizontal displacement and vertical subsidence, a new concept"sensitivity of displacement" are presented in order to evaluate stability of displacement normally. The characteristic of distribution of rockmass displacement along the longitudinal direction of road tunnel related to geological tectonics is concluded. It can be used for reference of design, construction and research of road tunnel. 相似文献
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20.
The cable's motion was modeled by a spring-mass-damper system. The flow field was calculated by RSM combined with the enhanced wall function model and the vibration equation of the cable was solved by the Four Step Runge-Kutta Algorithm, which was written into FLUENT software to be analyzed. It was adopted to analyse the factors influencing vortex-induced vibration of submerged floating tunnel cable, such as mass ratio, damping ratio of the cable and whether to consider streamline movement. The main conclusion included: mass ratio has little influence on the transverse vortex induced vibration amplitude of the cable, but has a big influence on the region of the reduced velocity; damping ratio almost has little influence on the region of the reduced velocity of cable's viv, but has an influence on the cable's vibration amplitude significantly; In the case of low-mass ratio, considered the impact of the cable streamline movement, the transverse vortex-induced vibration amplitude is bigger than not considered the case. 相似文献