Applied Mechanics and Materials Vols. 204-208

Abstract: There are long spans and various types of lining of highway tunnels under different geological conditions. It is challenging to obtain accurate geological condition data of tunnel, the existing tunnel design theories and methods are not mature either. Meantime, the stresses of tunnel during the stage of design, construction, operation and maintenance are also changing with time. Therefore, it is difficult to discover the root causes of the highway tunnels defeats, also because of the joint influence of the above factors. Through the broadly investigations of defeats of highway tunnel, the reasons of these defeats was analyzed and classified from four aspects, external forces, design methods, construction phase and deterioration of materials. More important, the general rules and association between the defeats and causes was studied and suggested following the brief introduction of the highway tunnel defeats.

Abstract: Based on the theory of soil-structure interaction, the underground structure and surrounding soil as a system, and the finite element analysis model is established, and finite element dynamic analysis method is implemented, the three seismic acceleration time history of the different spectrum characteristics is inputted, the seismic effect on the surrounding ground of underground structure is analyzed. The results show that the effect on dynamic response is the limited range and not significant, when seismic design of structures on the surrounding sites is implemented, additional dynamic response on surrounding sites does not need to consider.

Abstract: Shilin tunnel is a separated bi-directional four-lane highway tunnel, and its distinctive geological conditions and fault structure result in frequent geological disaster like large deformation. Construction of tunnels were seriously hampered, and the project was delayed, and the cost increases simultaneously. During construction of Shilin tunnel, accurate forecast of geological condition of surrounding rocks and possibilities of large deformation disaster was done through long distance TSP detection and short distance geological radar detection. Then Effective forecast on large deformation disaster to ensure safety of tunnel construction was carried out through adjusting excavation methods and support parameters, and close monitoring crown settlement, convergence, pressure of surrounding rock and pressure of steel-arch. This way is effective for like large deformation under similar conditions, this successful experience will apply reference for similar projects.

Abstract: To South-to-north water transfer project as the background, and based on the Peck formula, this paper educes the formula of settlement and internal force which caused by disturbance of the tunnel of the buried pipeline. Considering the different depths of the buried pipelines, the different diameter of the tunnel, the spacing interval between different tunnels and the depth of different tunnels and so on, this paper analyzes the effect of the twin-parallel-tunnels passing through construction on buried oil & gas pipeline. The research shows that the tunnel diameter has no effect on the width of surface subsider and the deflection of buried oil & gas pipelines, but it has great influence on pipeline internal forces. The spacing interval of tunnel has almost no influence on pipe deflection but has effect on the maximum internal force. Different depths of the tunnel contributes much to the rule of pipeline settlement and the distribution of internal forces, and it has greater influence on the internal force than on the pipe deflection . The relationship between the effect and the depth of the tunnels is non-linear. With the tunnel depth increasing, the hazardous conditions of the pipelines show significant improvement.

Abstract: Based on electromagnetic propagation theory, and used reflected wave detection method of Ground Penetrating Radar. To detect the tunnel with empty areas, void areas, non-dense areas, voids and other defects by the GPR. According to Jianshan Tunnel on-site detection, combined with practical examples to illustrate the GPR as a mean of nondestructive testing. The existence of tunnel defects and their reasons are analyzed comprehensively, and a series of processing measures are proposed.

Abstract: Baixugong tunnel is a big karst tunnel in Qing-Lian highway, and the construction environment is complexity. The structure of pile-pile cap-supporting wall-connection beam is used to treat the karst cave tunnel. Using simulation results and monitoring data to reveal the influence of tunnel excavation to treatment structure. The treatment structure in the karst tunnel is safe and reliable. The supporting wall stress and pile strain all increase accelerating during the advance of excavation face, then stabilize gradually. The construction simulation results are similar with the monitoring data, which demonstrates the important role of treatment structure in the karst tunnel.

Abstract: This article refers to the concept of intrinsically safe that emphasizes the production process, machinery equipment and fixtures which can create a safe production operating conditions for the operator. Combined with the tunnel engineering live telecast, for the complex geological conditions and the difficult safety control of the tunnel engineering, and through the essential safety of tunnel construction analysis, the tunnel project risk will be control effectively.

Abstract: It is a kind of effective way to study blasting to joint rock mass using the finite element method, in which the key is algorithm and model building. Comparing the relationship of explosive and blasting structure simulated by adopting Lagrange method and ALE method, the paper considers that Lagrange method is more close to practice, and could finish numerical simulation analysis of the intact rock blasting.

Abstract: The measurement of tunnel water inflow is not only an important basis for engineering design changes, but also an effective verification of design. This paper combines with the analysis of the measured data of groundwater of large water inflow section, which appeared in the construction of high-speed Jianfeng mountain super long tunnel in Fuling Fengdu, Chongqing city, and detailed information of hydrological survey results. This paper has re-evaluated the engineering geology and hydro-geological of large gushing sections to clear the reason of water inflow, the development trend characteristics of groundwater and stability of surrounding rock. It is shown in this paper that the measures such as strengthening the support parameters, optimizing the waterproof and drainaging design schemes, and other measures can be adopted to ensure the safety of tunnel construction and effectively realize the concept of dynamic construction.

Abstract: Based on the Hejiazhuang tunnel on the Zhengzhou-Xi’an passenger dedicated railway,forcing cases of systematic anchor was studied in loess tunnel with large cross-section and forcing characteristics of systematic anchor at vault and sidewall parts were obtained; Causes that the forcing difference varies much were analyzed from the perspective of the law of radial displacement attenuation and distribution form of surrounding rock pressure，the related conclusions will offer reference value and guiding significance to the design and construction of such tunnels.