Using vegetation to stabilize slopes, based on the root-soil interaction effects, to improve the Earth's environment has been verified and validated by many researchers. This study investigates ...whether vegetation is also essential to the retaining wall-backfill system under earthquake conditions. In accordance with the conclusions from the history studies of geotechnical centrifuge experiments on pile-soil interaction and on a representative mechanical model of a general woody root system, a numerical model considering dynamic root-soil interaction effects is built and a finite element analysis procedure is conducted in this paper for capturing the weakening retain-wall behaviour of vegetation. The result shows that excess pore pressure should be evaluated to eliminate the harm coming from the conflict between landscape and geotechnical engineering when trees are planted on top of a retaining wall.
The main influencing factors on its nature of complexity and indetermination are analysed deeply in this paper. Super Decisions software of ANP (Network Analytic Hierarchy Process) is used to solve ...the weights of all the influence factors. Use them as the initial weights to train SOM neural network for the fine-tuning; a new ANP-SOM model which consider to various factors, levels and impact of each other feedback synthetically is pretended. This model is well-adjusted, convergence and precision. It was used in forecasting of Xi'an Tunnel deposition and has achieved a good predicted result.
The thermal infrared (TIR) radiation in the deformation and progressive failure of coal roadway and the mechanism of thermo-mechanical coupling were investigated. The experimental achievement showed ...that the surface TIR temperature (TIRT) rose non-uniformly with the load increase before the stress peak and TIR radiation caused by stress concentration, shear band and bolted area, was much stronger and higher than that caused by stress relaxation, week friction and tensile fracturing. The bolted ranges were determined from the change ratios of TIR temperature of the different areas of the bolted surrounding rocks. The infrared thermal image anomaly appeared with the macro-cracks development in the progressive failure of bolted roadways, which reflected the spatial and temporal features of infrared precursor respectively. The infrared thermal image precursors were classified as TIRT increment region and TIRT constant region to disclosure the damage evolution and localization behaviours of bolted roadways.
The paper discusses about the level crossing safety policy of the Dutch government. It deals about the role of the government with respect to rail transport traffic safety. The paper presents some ...proposals to improve safety measures on the level crossing. It also discusses about the traffic campaign which triggers a lot of study and profoundly influences road infrastructure design and traffic regulation equipment.
Tunnel modelling is one of hot research areas on digital mine. Analyzing the basic elements and the topological relationship of the 3D tunnel model, 3D tunnel model with collapsible fractures is ...proposed. Data model of 3D tunnel is conducted in-depth study; data structure of 3D tunnel model with collapsible fractures is defined, and the key issues of the model are studied. On that basis, modelling method of the 3D tunnel model with collapsible fractures is detailed studied, and it is carried on programming with Java3D. The result shows that, 3D tunnel can be reasonably described with the model, and the model can be used to model the 3d mine geography network and to analyze the applications based on the 3D mine geography network.
The gangue cemented backfilling hoist mechanism in coal tunnel adopts forward-pushing combined linkage structure. The initial size of the hoist mechanism is obtained by the graphing method and the ...simulation model is established based on the size. Then the dynamics analysis of the hoist mechanism is done to test its interference condition and to analyze the forces exerted on the key parts. The dynamics simulation is applied to do the static analysis of the triangle linkage combined with the finite-element method. Analysis results show that the design of the hoist mechanism is correct and can meet the demand of the gangue filling system in the coal tunnel because there is no interference phenomenon and the force curves have no mutation during the motion process.
The increase of underground infrastructure implies a need to make rational and efficient use of underground space. Therefore, new tunnels have to be constructed more often in close proximity to the ...existing tunnel and the multi-line tunneling cases are usually encountered in situ. The deformation of the existing tunnel in soft clay during the construction is studied with the 3D finite element numerical simulation method. In order to simulate the shield obliquely crossing the existing tunnel, thin-layer elements are employed in the 3D finite element model. Furthermore, the complex tunneling procedure is fully considered. 3D simulation for lining installation and grouting process has been realized. Finally, the results from present approach are compared with the measured data, good agreement is obtained. It may provide certain basis to draw up correctly protective measurements of metro tunnels influenced by adjacent excavation. (5 pages)
Based on a detailed investigation and analysis, the present situation of shield tunneling for Beijing metro construction was studied. The main problems of shield method in the planning of the ...projects were as follows. First, continuous tunnel sections constructed by shield method were only a few; second, the efficiency of shield machine was low; third, the time used for non-driving tasks in shield tunneling was too long; fourth, the construction period using shield tunneling could not be guaranteed; and finally, the additional cost of shield tunneling was high. Detailed analysis indicates that the major cause for the problems was the contradiction of construction time between shield tunnel sections and adjoining stations, with the additional cause being that construction organization of shield tunneling was not well planned, that is the problem of shield machine passing the station was not well solved. A solution to the problems was put forward: let the shield machine pass a series of stations in the line first, and then construct the stations by cut-and-cover method or mining method at proper times. Such scheme shows great advantages in improving the quality, increasing the speed and reducing the cost of metro construction.
To improve control precision of automatic cutting, by analyzing process path, key stages were found out which could give rise to roadway tunnelling direction error and cross section borderline ...roughness error. Different swing speed control methods of cutting arm were adopted in different stages which were slow start control at the beginning of cutting and slow stop control in each cutting step. Internal displacement sensors were used in driven cylinders of roadheader cutting arm to calculate the space position of cutting head and reflect swing speed of cutting arm. The method has been tested and verified on EBZ200 roadheader. The results indicate that slow start of automatic cutting could reduce vibration and prevent the change of machine body position and orientation; slow stop could reduce the control delay and improve roadway borderline precision.
Safe by design, is the aim of all conscientious design houses involved in safety critical designs. Road tunnel control systems are regarded as safety critical because a tunnel is the most hazardous ...environment to road users and those involved with the maintenance of road structures. Road tunnel systems' interfaces with classical systems such as COBS and new control elements such as TSS make it particularly difficult to analyse for safety requirements. Good design ethos although necessary for a safety critical system is not sufficient on its own. System safety is a process that has to be enshrined into the design process in order to deliver a "safe design". This paper highlights a relationship between the safety activities and the design process for a tunnel control system that helps achieve the aim of safe by design.
