Beijing Municipal Engineering Research Institute

Beijing, China

Beijing Municipal Engineering Research Institute

Beijing, China
Time filter
Source Type

Zhao J.,Beijing Jiaotong University | Zhao J.,Beijing Municipal Engineering Research Institute | Niu X.,Beijing Jiaotong University | Niu X.,Beijing Municipal Engineering Research Institute | And 3 more authors.
Modern Tunnelling Technology | Year: 2016

This paper proves that the application of a numerical simulation method is reliable for studying the influence of tunnel excavation on an adjacent pile group by comparision of the two-phase method and numerical simulation method. Based on the Mohr-Coulomb elastic-plastic yield criterion, a three-dimensional numerical model was established with the finite difference numerical analysis software to study the variation law of the shielding effect of a pile group under different stress release rates, pile spacings and pile lengths. The analysis results show that the stress release caused by tunnelling has little influence on the shielding effect; the curves of the pile group shielding effect coefficient decrease with the increase of pile spacing except for the pile settlement; the influence of pile length difference on the shielding effect is more complicated, because the variation of various indexes does not exhibits the same law with changing of the pile length. © 2016, Editorial Office of "Modern Tunnelling Technology". All right reserved.

Zhang D.,Beijing Jiaotong University | Liu S.,Beijing Municipal Engineering Research Institute | Ren S.,China Railway 20th Bureau Group Co.
Modern Tunnelling Technology | Year: 2016

Using the Daliangshan tunnel on the Lanzhou-Xinjiang railway as an example, and based on field monitoring and 3D numerical simulation, an analysis of the force applied on the support was carried out for the high-geostress tunnel constructed by the three-bench seven-step method, focusing on the contact pressure between the primary lining and surrounding rock, the tension-compression stress applied on the steel arch and relevant deformation rules. The results show that: 1) the lining deformation is basically within the scope of the designed settlement control index of 350 mm and the requirements related to settlement and convergence in the Code for Design of Railway Tunnel; 2) the contact pressure and the deformation of the primary lining may increase with the construction steps, and both maximum values occur at the haunch of the sidewall, of which the maximum contact pressure is 845.8 kPa and the maximum convergence is 365 mm; 3) the minimum principal stress σ3 of the primary lining gradually increases with all behaviors as compressive stress, with an absolute value that is greater than the maximum principal stress; 4) the minimum principal stress σ3 of each point reaches its peak and later becomes stable after closure of the invert; and 5) large plastic zones may occur during tunnelling, of which the spandrel and the tunnel bottom have the rapidest plastic development, showing that invert closure is the key to deformation control. Thus, it can be seen that the primary support should be closed as early as possible during construction so that the increase of stress can be reduced and safety can be improved. © 2016, Editorial Office of "Modern Tunnelling Technology". All right reserved.

Zhao J.-K.,Nanjing Agricultural University | Huang S.-J.,Nanjing Agricultural University | Tao S.-Z.,Beijing Municipal Engineering Research Institute
Lecture Notes in Electrical Engineering | Year: 2018

At mesoscopic scale, the research proposed and established that concrete was a four-phase continuous and inhomogeneous composite material model consisting of coarse/fine aggregates, hydration products in cement, pores, and cracks. Under static and dynamic loads, micro-mechanics damage test simulation was based on the four-phase composite material model of concrete. The research’s content was concrete uniaxial compression test, three-point bending girder’s damage, and fracture under static and dynamic loads. The research found that the location of main crack in the beam shear was near the frailest part. The crack was along the bone and sand slurry’s combination, extending to the loading point direction and showing tortuosity. The crack extended surface was uneven, which was temporary deflection of the crack propagation direction due to the heterogeneity of concrete and aggregate distribution in it. The stress–strain curves of static and dynamic loads were similar, and the starting points of fracture initiation were basically identical. The stress wave in the specimen propagated back and forth many times, which led to the specimen fracture. Under the dynamic load, the elastic modulus of concrete was higher than that under the static load, and the numerical simulation results agreed with the experimental results. When the strain rate was less than a critical value, concrete strength increased slowly. When the strain rate was more than the value, concrete strength increased quickly. This research established five-layer, eight-layer, and 10-layer concrete frame structural models, which were simulated at the damage process of frame structure in strong earthquake. The study found that beam and column alternating failure belongs to the mixed collapse mechanism. The weaker the stiffness of foundation was, the earlier the failure time of lower floors was and the deeper the structural settlement was. The stronger the stiffness of foundation was, the earlier the failure point generated. The low floor failure of frame structure consumed a part of seismic energy, which reduced the effect of earthquake on upper frame structure partly. © Springer Science+Business Media Singapore 2018.

Zhang D.-H.,Beijing Jiaotong University | Liu S.-H.,Beijing Municipal Engineering Research Institute | Ren S.-Q.,China Railway 20 Bureau Group Corporation
Yantu Lixue/Rock and Soil Mechanics | Year: 2015

According to the characteristic curve of the surrounding rock via support in tunnel structures, the strength and the installation timing of the early supports can significantly influence the deformation and stress distribution of surrounding rock. Consequently, as an important part of the early supports in tunneling, the shotcrete support plays an important role in the deformation and stress distribution of the surrounding rock, depending upon the strength growth and hardening rate of the shotcrete after injection. To explore the effects of the strength growth and hardening rate of shotcrete on its early supporting performance, a series of shotcrete field tests was carried out on the tunneling sites. The variations of the strength and elastic modulus of shotcrete were investigated; and the effects of the hardening rate of shotcrete on its early supporting performance were determined. It is concluded that (1) The strength of the shotcrete develops fast and stably in the beginning; the average compressive strength after 24 hours reaches 6.5 MPa; after 48 hours, it increases up to 11.5 MPa. (2) In the surrounding weak rock, it is important to improve the early strength of shotcrete so that the surrounding rock deformation can be controlled. The greater the early strength of shotcrete, the more effective the early support. (3) The shotcrete hardening rate is an important factor controlling the settlement of the tunnel vault. Compared with slowly hardening shotcrete, the rapidly hardening shotcrete can reduce the settlements at the vault and the arch foot by 10.4% and 17%,respectively, and the horizontal displacement at the sidewall by 30.7%. (4) The effect of the hardening rates on the development of the plastic zone in the surrounding rock is insignificant. (5) The strength hardening process of shotcrete should be properly taken into account, and failure to consider the hardening rate of shotcrete may overestimate the supporting performances of the support and significantly underestimate the deformation of the supporting structure. ©, 2015, Academia Sinica. All right reserved.

Nie J.-G.,Tsinghua University | Wang Y.-H.,Tsinghua University | Cai Q.,Beijing Municipal Engineering Research Institute
Gongcheng Lixue/Engineering Mechanics | Year: 2010

In order to satisfy the requirements of practice, the floor has to be cast with openings. Thusly, the composite steel-concrete beams with whole openings in concrete slab appear. The problem of lateral stability of composite beams resisted sagging moment exists because of the whole openings. The elastic finite element mode is established to analyze the lateral buckling of the composite steel-concrete beams with whole openings in a concrete slab. Based on FEA analysis, the lateral displacement function and rotation function of a cross section is assumed so as to use Rayleigh-Ritz energy method. The formula to calculate the critical buckling load of composite steel-concrete beams with whole openings in the concrete slab is conducted based on Rayleigh-Ritz energy method. Then the parameter analysis is conducted. At last, the necessity of lateral stability of composite beams with whole openings in the concrete slab is indicated by the calculation example.

Nie J.-G.,Tsinghua University | Li F.-X.,Tsinghua University | Fan J.-S.,Tsinghua University | Cai Q.,Beijing Municipal Engineering Research Institute
Gongcheng Lixue/Engineering Mechanics | Year: 2011

Shear lag effect has significant effect on stress and deflection of composite beams. According to the elastic analytical model of composite beams, stress and deflection analytical solutions for the cases of simply supported composite beams and cantilever composite beam under uniform distribution load and concentrated load are derived by ignoring slip effect in the interface. By introducing effective flange width and effective sectional rigidity, practical design methods for considering shear lag effect of composite beam are presented, and the results calculated by these methods have good agreement with those obtained from analytical solutions. By comparing different design methods for composite beam considering shear lag effect from different countries, the simple practical design method presented in this research is found to have high accuracy despite of its simplicity.

He M.,Beijing Jiaotong University | He M.,Beijing Municipal Engineering Research Institute | Liu J.,Beijing Municipal Engineering Group Co. | Le G.,Beijing MTR Construction Administration Co. | And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2010

Based on a certain constructing running shield tunnel of Beijing metro side-crossing close to a high-rise building, using the finite element method calculation model and site monitoring method, the foundation characteristics of the high-rise building affected by the constructing shield tunnel are studied. In different construction stages, the variations of the foundation settlement and inclination of the high building are analyzed. The simulation results show that stratum vertical displacement has a sudden change near the high-rise building. Away from the building in an enough distance, the displacement curve becomes flat. From site monitoring results, the high-rise building inclined to the direction away from the tunnel prior to the shield closing to the building, while the building inclined towards the tunnel during shield crossing. The settlements of the monitoring points reach the maximum value when the shield is 10.0 m away from the monitoring surface. However, the settlements declined significantly when the shield is more than 60.0 m from the monitoring surface, and finally becomes stable. The simulation and the site monitoring results agree well. The conclusion would be helpful for the future similar shield tunneling projects.

Cheng L.,The MCC Group | Zhang P.,The MCC Group | Wang F.,Beijing Municipal Engineering Research institute
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2015

The misconception in soil and rock mechanics, the irrational methods of design and construction for anchored structures in ground exist in China, which frequently lead to accidents such as anchor failure, instability and even collapse of engineering structures. According to geotechnical investigations of typical engineering and engineering accidents, theoretical analysis and experimental studies, some mechanical conceptual problems which significantly affect the stability of ground anchorage were studied. The prestressed anchor has the advantages of providing the active resistance and transferring the tensile stress of structures to the deep stable strata and can be widely used to resist dumping, vertical displacement, shear failure along the foundation base and openings collapse. The section of anchor meeting the requirements of tensile stress, the length of free end of the anchor being long enough and the anchoring formations being able to fully mobilize the ground shear strength are basic elements for raising the tensile bearing capacity of anchors. The pressure-dispersive anchor significantly improve the load transfer effect and the anti-corrosion protection performance and has excellent mechanical and chemical stability. The time delay in anchor installation can be effectively controlled and avoided after excavation in the slopes and openings by timely applying tensile anchors and prefabricated reinforced concrete blocks as the high bearing capacity transfer structures. In order to improve the stability of large openings in high stress and low-strength rock, it is necessary to adopt the low prestressed anchors as the initial support, to strictly control the time delay of the installation of high prestressed anchor, to raise the initial prestressed value in design and to strengthen the control of the interaction between the surrounding rock deformation and anchorage resistance (stiffness). ©, 2015, Academia Sinica. All right reserved.

Ye Y.,Beijing Municipal Engineering Research Institute
Journal of Railway Engineering Society | Year: 2013

Research purposes: The reliability of the advanced geological forecasting for tunnel construction has puzzled engineering technical personnel all the time, and the accuracies of the forecasting result and the forecasting data are crucial to the tunnel construction. If the problems existed in the current forecasting methods and technologies are realized correctly, it will favour continuous improving the forecasting technical level. This paper discusses the main influence factors on the reliability of the advanced geological forecasting for tunnel construction and points out the problems and limitations existed in the current forecasting methods in the areas of the forecasting method, interpretation, space orientation, wave velocity orientation and survey capacity. Research conclusions: (1) Most of forecasting methods have limitations at present, so it is necessary to correctly understand and analyze the forecasting result. (2) Under the complicated geological condition, the comprehensively advanced geological forecasting should be conducted with many methods to verify and supplement them each other. (3) The forecasting reliability and precision can be enhanced by using the synthesized parameterand and space forecasting theory, method and technology.

Li D.,Beijing Municipal Engineering Research Institute
Advanced Materials Research | Year: 2011

With the modern process of city, subway becomes the best choice of resolving the traffic jamming because it is convenient and effective and well-environmental. As so far, there are three kinds of subway construction methods (shield tunnel, hidden excavated tunnel, pit and cover). Hidden excavated tunnel becomes the only choice in complex conditions because it is suitable. It is inevitable that hidden excavation leads to settlement and influence use of adjacent structure. That is even so when the big span tunnel excavates. This paper analyzes the action mechanism of construction scheme with central boring in controlling settlement according to a case in Beijing. At the same time, it analyzes the value and percent of settlement in each step of center drift method according to monitoring data in site. Finally, center drift method is effective measure to control settlement in big span tunnel and reduces the settlement in 5mm. As a successful case, it may be useful to future similar engineering. © (2011) Trans Tech Publications, Switzerland.

Loading Beijing Municipal Engineering Research Institute collaborators
Loading Beijing Municipal Engineering Research Institute collaborators