Journal of Railway Engineering Society

Research method: By analyzing still existing weaknesses after six large scale speed-up reconstructions of Zhengzhou-Wuhan section of Jing-Guang railway, such as inadequacy of the transport ability and lower train velocity, inappropriate transport quantity for developments and quality for the national economic markets, necessities of eliminating the only two remained velocity restrict segments are demonstrated. And through research into two engineering plans of reconstruction, the feasibilities of eliminating those two remained velocity restrict segments are discussed.

Research results: With above analysis, the paper eliminates the two remained velocity restrict segments, from Menmiao to south of Renhe and Changtaiguan to Chenjiahe. And it is feasible in technologies and reasonable in economies.

Research conclusion: Eliminating velocity restrict segments from Menmiao to south of Renhe and Changtaiguan to Chenjiahe, at the same time sloping down the gradient, can not only satisfy the requirements of passenger trains speed-up between Zhengzhou and Wuhan, but also suit a huge future goods transport demand for existent railways, so elimination of these two velocity restrict segments is the sooner the better.

Research method: Based on analyzed interaction between the engineering and environment, this paper summarized below design principles on coordinating between road engineering and environment for preventing the environmental problems.

Research result: (1)this paper summed up a leading principle in tunnel waterproof and drainage design of "water environmental balance" with choking up underground water, in order to prevent and control water environmental hazard of ground above tunnel and sluicing hazard in tunnel by establishing interaction chain between tunnel engineering and water environment; (2) this paper analyzed the relations between the slope height, support engineering and between protective of the slope and ecological environment; summed up a design subgrade principle of reducing slope height with support engineering, in order to advance prevention countermeasure for high cutting slope; (3) this paper analyzed the relations between engineering way of cutting slope of subgrade and response of rock-soil mass in the slope; gave up traditional engineering way, which cutting from up to low and support from low to up, to renew turn into a new ideal of design and construction, which is gradual support from up to low and beforehand reinforce in slope foot, in order to kept stability of the cutting slope; (4) this paper summed up a principle of accumulation and reclamation of waste in valley heat area, aiming at environmental problem caused by engineering waste soil.

Research conclusion: aforesaid design principles on coordinating between road engineering and environment can control main environmental problems which caused by road engineering in source.

Research method: The paper introduced the requirements for setting plumb points on tunnel portal, characteristics of geodetic quadrangle survey method, its application and calculation methods for inside work, and gave some concrete project examples.

Research result: The paper also expatiated the theories and methods applied to geodetic quadrangle survey method for tunnel control survey and raised out the geodetic quadrangle control net, is a quite convenient method with high precision for control survey on tunnel portals. Calculating method and application to concrete examples can be a kind of reference to selection of plumb points position, set of tunnel survey control net and treatment of data from inside work for similar tunnel construction.

Research conclusion: There are many forms for set of tunnel survey control net. We must choose the proper form according to the requirement of control survey and construction characteristics, to ensure the precision of control survey and be convenient to the construction.

Research method: Using technologies of communication, computer, control and artificial intelligence, this paper expounds basic plan of urban Intelligent Transportation System-Railway based on analysis of civil and abroad urban rail transit exert safe present, furthermore it expounds designing framework of urban rail transit synthesis supervision and control system and analyze its intension, logic framework, fabric information flow, physics framework and interface techniques.

Research result: Comparing with present system, intelligent synthesis supervision and control system has characters of supervisor extent widely, labor division clarity, concentration-managing, integration harmony exert and intelligent managing, it embodies human centered sufficiently.

Research conclusion: This system has scientific guiding denotations to future construction of civil urban transit supervision and control system.

Research method: Combining subway's actual conditions with the deciding target set in standards for the hazards of the stray current, selects polarized potential of the underground metal as the monitor parameter, and utilizes Cu/CuS04 as comparing electrode because of its qualities such as stable voltage, not easy to be polarized, low resistance and mechanical intensity. The core of the system's hardware is the microprocessor based on ARM7 whose high speed and rich connecting sources can easily realize the monitor and control function.

Research result: This paper showed us the online monitor and control system for accurately calculating the metal's corrosive degree and trend under the subway stray current.

Research conclusion: Although the subway stray current is largely corrosive, as long as one can take scientific measures, design reasonable automatic online monitor and control system, effectively reduce the loss of current's corrosion, and one' can ensure the subway's permanent safe operation.

Research method: In this paper, 4 group of model tests are carried out under the simulated field conditions to study the dynamic performances of the subgrade-bed for passenger dedicated railway line with different thickness and reinforced with the geocell. The length, width and height of the model are 7 m, 5m and 1.05-1.55 m. In order to simulate the action of the passenger dedicated railway line wheel load on the subgrade bed, the 5Hz cyclic loading is repeated 1.5 million times in every group of test.

Research result: In order to compare the model tests, the test in situ was carried out. Refer to the subgrade-bed without geocell, the dynamic stress of the subgrade bed with geocell is smaller and more uniform, the elastic deformation and the permanent deformation decrease obviously.

Research conclusion: By comparing with the live model tests, the strength and the stiffness of the subgrade-bed with geocell which thickness is 30cm can satisfy the demands of the passenger dedicated railway line.

Research method: The design method, construction technique, quality check method and cautions are described in details for reinforcing subgrade in soft soil zone by adopting composite structure of CFG pile-net and the mechanism of reinforcing subgrade in soft soil zone is analyzed and explored on the basis of an example of reinforcing subgrade in deep soft soil zone in trial section of one high-speed railway in Shanghai by adopting composite structure of CFG pile-net. The relative experiments and site test research are made on the reinforcement effect of two different pile lengths, the law of settlement deformation and gorged stress under embankment load.

Research result: The composite structure of CFG pile-net to penetrate soft soil bed with pile length of 27 m can meet the requirements of the capacity of subgrade in soft soil zone against high-speed railway (ballast track) and post-construction settlement of 5 cm after eight months of ending filling. This provides the reliable data and reference basis for design, construction and quality check of reinforcing subgrade in deep soft soil zone and provides the experience of building passenger dedicated railway line in soft soil zone.

Research method: Based on literature review of a large number of relevant domestic and international research findings, the research developments were investigated and summarized in detail, including the define of sloped weak ground, the behavior of stress and deformation of subgrade embankments on sloped weak ground, the stability evaluate methods of subgrade embankments on sloped weak ground and the test research and engineering practice of subgrade embankments on sloped weak ground. Furthermore, research efforts are needed to analyze the failure patterns, the influence to upper structures, the selection of reasonable stability failure criterion and engineering measures.

Research conclusion: To better understand of the structural responses and distress mechanism of subgrade embankments on sloped weak ground is necessary to enhance quality.

Research method: In this paper, the author analyzed the subsidence data gained by monitoring for settlement of red rock subgrade in soft soil zone after powder-spraying pile disposal adopting subsidence-pipe and the rules of subsidence for subgrade in soft soil zone, and made fitting by exponential function and forecast its final settlement value.

Research result: It is found that subsidence-pipe is made good use in the monitoring for settlement of red rock subgrade in soft soil zone, and the subsidence of subgrade in soft soil zone after powder-spraying pile disposal satisfies the temporarily criterion of high-speed railway.

Research conclusion: So it is reasonable to use subsidence-pipe monitoring and forecast means in red rock subgrade in soft soil zone.

Research method: As the practical engineering of Yangtze River Bridge for example, this paper discussed the key points, construction technology and test method of water proof in situ.

Research result: The result of test in situ revealed that the permeability of all kinds of strata soil was about 10-5 cm/s in an average water pressured state, but maybe increases so that strata soil maybe hydrosplitted in the water pressure that was more than 0.3 MPa.

Research conclusion: The conclusion demonstrated that the curtain grouting technology could prevent water very well when holes were dug.

Research method: The mechanics analysis is made to the load born by temporary beam by adopting the method of finite-element analysis and establishing mathematics model.

Research conclusion: The vertical deflection value of temporary beam under effect of real load is very close to the calculated result after considering the impact factor by adopting the research method. The sample result of displacement in span of temporary beam is also very close to the calculated result, only a little smaller than the calculated result. The frequency of sample D24 temporary beam is 3.7236 Hz and is larger than theoretically calculated result by 8.8 percent. Therefore, it shows the temporary beam has enough rigidity.

Research method: Based on grillage theory for the skew bridge of continuous girder to calculate and simplify about the structure, and make use of just the principle of rigidity equivalent proceeds analysis to the original construction and makes use of the analysis method of FEM proceed to scatter for the construction, at the same time utilize SAP2000 procedure of FEM to imitate analysis to simple one dose of models of grillage at the same time.

Research result: For begging the solution analysis breadth, inclined suffer the continuous beam of dint sophisticate, similar with this structural a box beam as well as entity plank beams and offered a kind of practical and simple and convenient method by the continuous girder with complicated strength.

Research conclusion: By calculating the engineering example and comparing with the calculating result for shell model, grillage theory has better use value in construction.

Research method: A large amount of convergence measurement cross-sections are installed in the job site and long-term monitoring and measurement are executed. This paper analyzed convergence data of surrounding rock in the tunnel and effects.

Research result: It is pointed that deformation of surrounding rock has the characters of time pertinence and space pertinence. The deformations of the surrounding rock contain 3 stages: rapid-deforming stage, slow- increasing stage and nearly-stable stage. The deformations of the surrounding rock mass of Xinqidao liang tunnel has such features as uniform deformation, rapid convergence, small deformation and crown settlement larger than the horizontal convergence.

Research conclusion: These deformations are functions of many factors such as geological conditions, technology and ambience. Results indicate that the surrounding rock of the tunnel is good with high self-supporting capability, the design and execution technology of the excavation and reinforcement of the tunnel is scientific and rational and the reinforcement structure is strong. The analysis of rock deformation feeds back construction, and produces satisfactory effects.

Research result: Four typical geological mechanics models to analyze interrelation between landslide and tunnel deformation are given. And the mechanical patterns of tunnels situated different place in landslide are analyzed. On the basis of above, the engineering measures to control tunnel deformation at landslide site are studied too. The viewpoint is set forth that engineering measures should be suitable to the deformation features of tunnels, and the specific choosing method is given.

Research conclusion: The relative position between tunnel and sliding plane is the major cause to determine the deformation features of tunnel; the engineering measures should be suitable to the deformation features of tunnels.

Research method: After occurrence of burst water, the following emergency measures are taken on site. Toroidal reinforcement and lateral support are conducted by I-steel, and holes are drilled on right side wall to drain water and decrease water pressure. After stabilization of water volume, the radial reinforcement is conducted for Fault F3 by grouting to block water. The deformed grid steel frames are displaced by steel frame I20 and secondary lining is laid in time.

Research result: After treatment by adopting technical measures of "radial grouting reinforcement-primary support reinforcement-laying secondary lining", only local vadose water occurs on Fault F3 with water volume of one cubic meter per hour. The treatment result is good.

Research conclusion: First, it is known from burst water accident if the watery situation of underground river occurs around tunnel (within 100 meters), once the surrounding rock breaks up, even water is not burst during tunnel excavation, but it is difficult to ensure no occurrence of burst water after ending primary support or no occurrence of problems in service of tunnel. With concept increment of "Strengthen the fundamental and weak the trivial, and service for operation" for tunnel construction, it is necessary to reinforce in advance and make provisions before troubles occur to such geological structure. Secondly, it is an effective way to treat and prevent occurrence of burst water in similar geological structure of Fault F3 of Bieyancao Tunnel.

Research method: The formation of geological disaster and its direct relation with environment worsening are demonstrated through analysis of the influences on water and land resources by existing design principle.

Research conclusion: It is proposed that the fully closed design scheme should be adopted for key area, namely in combination with advanced geological survey, the pre-reinforcement should be conducted to the ahead burst mud area with complex geology before geological disaster of tunnel occurs in order to make no worse of environmental geology.

Research method: Through the analysis of all kinds of schemes made for reactive-load compensation and harmonic treatment to traction substation in China, the suitable reactive-load compensation scheme is present to the traction substations of Yichang-wanzhou Railway Line according to the real situation of the line.

Research result: If the scheme of controllable compensation reactor is adopted on Yichang-Wanzhou Railway Line, although it can automatically trace the system and make compensation with simple devices and high reliability, but it makes harmonic current, large noise and great loss. If the scheme of crystal shutter tube turnover capacitor (TSC) is adopted, it needs investment of 1.8 million Yuan to substation. If the scheme of fixed filter (FC) plus crystal shutter tube adjustable reactor (TCR), it needs investment of 1.95 million Yuan to substation.

Research conclusion: TSC Scheme only can give step capacity reactive power and more groups, lower filtering effect. SVC Scheme of TCR plus FC is a suitable scheme of reactive-load compensation for traction substation of Yichang-Wanzhou Railway Line

Research method: This article analyzed the distributing of zero sequence current when single phase grounding fault occurred along the circuitry. A fault location method based on General Matrix Arithmetic is proposed for railway power supply line, and the method is validated.

Research result: The method composes a distributed system made up by STU, FTU and supervise terminal. Abandoned the previous method, which locates faults by examining the zero sequence voltage and comparing the zero sequence current of each line in the electrical power station, use the zero sequence current of each switchgear spot only.

Research conclusion: In condition of laboratory, the new method can locate and isolate faults within 10 seconds, it can provide reliable gist for fault lookup and elimination.

Research method: There is less experience of this construction technology. In order to guarantee the construction smoothly to carry on, this paper calculated with ANSYS software simulated the excavating process of several layers excavating and stress discharging in advance for big cross-section of underground factory house, analyzed the nonlinear numerical model to ensure the surrounding rock mass in stable condition and to reinforce the weak area in time and gave the doable estimate to this construction method.

Research result: Through comparing and analyzing the monitoring information with numerical result, the paper approved this estimate was right and reasonable. At the same, comparing with traditional construction method of layer by layer excavating, it also approved the construction method of several layers excavating had its advantage.

Research conclusion: The paper proved theoretically that the construction method is doable. In many aspects, this new method is better than traditional method of layer by layer excavating and provides an effective construction method for the big underground cavities fast excavation.

Research method: Based on the authors' long time construction experiences, this paper analyzed the effects of soil improvement, scope of the soil improvement and application of construction for soil improvement. Finally, this paper summed up the accidents caused by worse soil improvement and the supervising method for soil improvement.

Research result: This research shows that the differences between soil improvement of end tunnel and general soil improvement are not only in strength demand and also in anti-seepage demand. For soil improvement of end of tunnel, economy is mended to be considered, which is determined by length, width, methods of soil consolidation. That is to say that soil improvement deals with whether the risk and width of soil improvement

Research method: The numerical simulation calculation is carried out to the aerodynamic force of the train under wind-break wall with two dimension incompressible viscous N-S equations, when the cross-wind speed is 35.1m/s, the height and position of wind-break wall and the height of embankment are different.

Research results: the best height and position of wind-break varying with the height of embankment is established.

Research conclusion: The best height of wind-break wall is decreasing with the increase of height of embankment, and the extent is smaller. While the best position of wind-break wall has a little change from 3.4 meter to 3.5 meter basically.