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2015 Vol. 32, No. 11
Published: 2015-11-16
Geology and Subgrade
Railway and Rail
Bridge Engineering
Tunnel Engineering
Survey and Design
Urban Rail Construction
 
       Survey and Design
1 Discussion on the Determination of Static Lateral Pressure Coefficient from Flat Dilatometer Tests
CHU Tuan-jie
Research purposes ： At present，there are two main methods of determining the static lateral pressure coefficient from the flat dilatometer tests which are the theoretical formula method based on the Mindlin solution and elasticity theory and the experience formula method based on the test data of the fat dilatometer tests. Through this research, which of the two methods is more accurate for calculating the static lateral pressure coefficient of the soil layer is determined，and the method can be applied to the engineering exploration in the future.
Research conclusions ：( 1) The theoretical formula method based on the Mindlin solution and elasticity theory is linear，and the result is difficult to determine because it changes with the change of the ratio of the comer point stress and the center point stress. (2) The experience formula method based on the test data of the flat dilatometer tests is nonlinear， which is in line with the characteristics that soil is non - elastomeric，and the soil layers from the different regions and different genesis. So the experience formula method based on the test data of the flat dilatometer tests is more suitable for engineering practice. (3) This research result can provide reference for determining static earth pressure coefficient in the railway，subway，highway and other engineering survey.
2015 Vol. 32 (11): 1-4 [Abstract] ( 2832 ) HTML (1 KB)  PDF  (360 KB)  ( 2647 )
       Geology and Subgrade
5 Research on the Characteristic and Genesis of Q2 Vermicular Red Clay in Ningxiang of Changsha - Yiyang Railway Hot!
WANG Ying – he
Research purposes： The Q2 vermicular red clay was widely distributed along the Changsha - Yiyang railway where soil thickness is 5 ~30 m. It is the key problem to choose proper method to treat this type of soil because the settlement of intercity railway subgrade must be controlled strictly. Based on the site survey, particle - size analysis, chemical component analysis , X - ray spectrometry analysis and microstructure , the material composition , structure and genesis of the Q2 vermicular red clay were studied systematically，which can provide a reference to choose the foundation treatment method.
Research conclusions:(1) The clay was the preponderant particle in which the content was about 65% in the soil of Ningxiang , and the red soil contained more clay than the white soil. (2) The most component was SiO2, the next was Al2O3 and TFe2O3, and the three materials were mor^ than 85% in the soil. (3) The iron element of the red soil is triple that of the white soil. (4 ) The framework of the white soil was schistose, and the contact between particles mainly contained surface - surface and surface - line contact. (5) The framework of the red soil was more inordinate. (6) The vermicular red clay was not formed in onefold climate, and underwent multistage climate, so it was a kind of compound paleosoil. (7)This research result provided references to the genetic study of vermicular red clay.
2015 Vol. 32 (11): 5-9 [Abstract] ( 2719 ) HTML (1 KB)  PDF  (711 KB)  ( 2507 )
10 Research on the Soil Temperature Distrilbution of Guanzhong Area in Spring
LI Ying -jie,ZHANG Bei，YANG Chen -xi，WANG Pei,LIN Qi -cai
Research purposes ： Soil temperature in earth "s surface is an important parameter of agriculture and underground projects. During March and April 2014, soil temperature of 6m depth in 4 typical sample points was researched in Guanzhong area by soil temperature techeometer and embedded thermometer probe.
Research conclusions: Through analyzing the spatial variation of soil temperature with depth in the different points and under different weather conditions， 4 conclusions were drawn as following ： ( 1 ) On the whole， soil temperature of shallowlayer in the Guanzhong area increased with the increase of the depth in spring, and reached 17 °C ~19. 5 °C in the end，and increasing amplitude became smaller and smaller with the increase of the depth. (2) From the space dimension， soil temperature variation in Guanzhong area was obviously different， the change was single in some samples，and moreirregular in others. ( 3 ) The differences of physicochemical properties, such as soil composition, and the cumulative effect of solar radiation were the primary cause of irregular variation of soil temperature in spring. (4)The rain had bigger influence on the soil temperature. Under the influence of the infiltration of rainwater， the soil temperature difference became small, and the soil temperature change with depth presented complicated alternation of up and down. (5)These conclusions can be used as an important reference of underground facility design， construction， operation and management in Guanzhong area.
2015 Vol. 32 (11): 10-13 [Abstract] ( 3062 ) HTML (1 KB)  PDF  (488 KB)  ( 2656 )
14 Research on the Dynamic Resj3〇nse of Sand Flow and Railway Culvert Hot!
LI Kai - chong,SHI Long,ZHANG Fang,JIANG Fu - qiang
Research purposes ： In the wind sand disaster areas，when air - sand flow passes through the railway culvert， afected by the boundary effect and narrow^ tube acceleration effect，the obvious disturbance of airflow^ appears，and sand will be carried or deposited around the culvert. The accumulation of wind - blown sand in culvert will influence the normal operation of the train. Aiming at the above problem，this paper studied particularly the formation mechanism of wind sand disaster in culvert by using numerical simulation and field test which provides some theoretical basis for disease treatment and railway design.
Research conclusions:(1) The local high - speed vortex area at inlet of culvert is fomed，when the air flow passes through the railway culvert. Wind speed gradually decreases with the marching of airflow in culvert, but the value is still slightly higher than the outside wind speed. (2) Due to the affection of accelerating effect，vertical gradient difference will be amplified，and stratification phenomena of speed will appeared. (3) Wind speed decreases gradually，and a large amount of sand fall when wind - sand flow moves along the diversion dike. (4 ) The curves of wind speed are arch shapes, which are affected by architectural form. The phenomenon of wind - blown sand appears at the both sides of culvert portal，which are the lowspeed areas of air flow. (5) The research result provides a certain theory support for
wind sand disaster prevention of culvert along the railway line.
2015 Vol. 32 (11): 14-17 [Abstract] ( 2825 ) HTML (1 KB)  PDF  (690 KB)  ( 2577 )
18 Analysis of the Influence of Moisture Field Transfer on the Stability of Subgrade in Alpine Region Hot!
SUN Wen1, WU Ya - ping1, LI Jing1, SONG Li2
Research purposes: The construction of subgrade engineering in alpine region will form a secondary disease, secondary disease of the railway, highway subgrade and other buildings will produce a variety of hazards. It is very important to study the formation mechanisrm and development of the secondary unfavorable permafrost in the high altitude area to ensure the stability and safety of the project. Through the numerical analysis of thermal thaw sliding collapse and freeze up mounds of secondary unfavorable permafrost phenomenon, this paper put forward prevention and engineering protection measures of secondary disasters.
Research conclusions:Through study on the formation mechanism and change process of secondary harmful disasters in alpine region , the following conclusions are drawn ： (1) Considering effects of moisture field transfer , the influence of hot melt sulcus on the lateral inhomogeneous deformation of the subgrade will increase , which will form the disease of subgrade longitudinal cracks , seriously affect the subgrade stability. (2) Moisture field transfer makes the temperature field change significantly intensify and the deformation around the hot melt sulcus increase , repeated action of frost heave and thawing settlement under the influence of moisture field transfer will cause water into the subgrade side , which will threaten the stability of subgrade and safety of train operation , so it is necessary to take correct engineering measures to governance. (3) The research result provides a theoretical basis for the engineering construction in permafrost regions, and has the reference significance to the prevention of secondary unfavorable disaster.
2015 Vol. 32 (11): 18-22 [Abstract] ( 3091 ) HTML (1 KB)  PDF  (491 KB)  ( 2609 )
23 Support Design and Monitoring Analysis of Foundation Pit Adjacent to High Speed Railway in Soft Soil Area
YU Ting - xin
Research purposes: The foundation pits which are adjacent to high speed railway are increasing, causing settlement easily in soft soil area which affects safe operation seriously. At present support design and monitoring technology of foundation pit adjacent to high speed railway in soft soil area is immature. Design experience and monitoring data is extremely deficient. The paper relying on the example of foundation pit adjacent to high speed railway in soft soil area researched the support design and monitoring.
Research conclusions :( 1) Suggestion of strengthening support according to deformation was put forward，which reduced roadbed settlement. (2) Settlement time of high speed railway after foundation pit excavation in soft soil area was long and it had creep characteristics. After each layer soil excavation，settlement rate was from the larger to the smaller and the final settlement value was very large. (3 ) In the same location settlement of shoulder, catenary column and track was basically same. Settlement rate and value in the central part of foundation pit was larger than both sides and the part far away from foundation pit. (4) Settlement at toe of slope was smaller than shoulder, catenary column and track. (5)The settlement of junctional zone between foundation pits was larger, caused by simultaneous excavation and dewatering.(6 ) The effect distance caused by excavation and dewatering was about five times of foundation pit depth. (7 ) Experience of design and monitoring can be referred to for foundation pits design adjacent to high speed railway.
2015 Vol. 32 (11): 23-29 [Abstract] ( 2737 ) HTML (1 KB)  PDF  (1664 KB)  ( 2613 )
30 Research on the Shaking Table Test of Governance witli Double - row Anti - slide Pile Appiled in Large - scale Multilayer Sliding Surfaces Landslide
WU Hong - gang,FENG Wen -qiang
Research purposes ： As the accelerating pace of construction of domestic highway, railway and civil aviation, there has been many great propulsion engineering landslides in the high intensity seismic region of western China, which always had characteristics of multilayer and multilevel significantly. Double - row anti - slide pile was the effective measures to control the large landslide. Combined with the typical engineering examples such as Yushu airport road landslide in Qinghai Province and Panzhihua airport landslide in Sichuan Province, double - row anti - slide pile is studied how to govern the large sliding surface landslide by the large - scale shaking table model test in X , Z and XZ direction three kinds of load conditions , the characteristics of dynamic response of double - row anti - slide pile and deformation & destruction of landslide were analyzed.
Research conclusions:(1) Double - row pile tests showed that the effect of governance with double - row pile on large - scale multilayer sliding surfaces is obvious , which reflected very well the design concept of 11 no collapsing with strong earthquake" . (2) Durng the tral , the overall defomation mode of slope is mainly tensile - shear failure , the platform at the back of slope is given prcTy to seismic subsidence，the sliding body is layered and forward，and the interface effect is obvious , sliding surface gradually developed to deep , clamping effect was significant on both sides of the model box. (3 ) Test data analysis showed that thrst allocation proportion of two rows anti - slide piles was not the back row piles bore most of the landslide thrnst (mainly came from landslide thrnst of the deep sliding body) , and landslide thrust ratio was smaller in the front row piles. (4 ) The study has very important theoretical and practical significance for dynamic performance analysis of the double - row pile.
2015 Vol. 32 (11): 30-36 [Abstract] ( 2704 ) HTML (1 KB)  PDF  (1110 KB)  ( 2593 )
       Railway and Rail
37 Effects of the Interaction between Beam and Rail on Slab Warping on Subgrade - bridge Transition Section Hot!
CHEN Rong，XING Jun,MA Xu -feng，TIAN Chun -xiang，WANG Ping
Research purposes ： In order to clarify the influence of longitudinal mechanical behavior between the bridge and the ballastless track on the warpig of reinforced concrete slabs in the subgrade - bridge transition section， a mechanical model including CWR and slab on bridge is set up, so as to study the effects of the restriction of bridges and track structure，the rail additional expansion and contraction force，and the temperature gradient of the slab on the slab warping.
Research conclusions: (1) When considering the restriction effect of bridge and rail，the upwarpig increased by 28% reaching to 2. 5mm compared with no consideration of the bridge and track structure. When considering the rail longitudinal force，the upwarpig of the slab decreased by 44% reaching to 1 4mm，and the stronger rail longitudinal force results in more reduction of the slab warping. (2 ) When considering the positive temperature gradient effect, the
warpig increased by about 43% reaching to 2. 1 mm. The negative temperature gradient effect made the warpig decrease by 14%. ( 3 ) The more increase of the bridge temperature led to the smaller upwarpig， but the impact decreased gradually when the bridge temperature reached high enough. (4) The warpig o the slab greatly increased by  1.2 times reaching to 7. 8 mm when laying the rail expansion joint ( REJ) in the beam gap of large - span bridge compared with lay small resistance fasteners in main bridge. (5 ) The research conclusions have certain guiding significance for the optimization of the design theory and engineering practice in the subgrade - bridge transition section.
2015 Vol. 32 (11): 37-42 [Abstract] ( 2880 ) HTML (1 KB)  PDF  (713 KB)  ( 2518 )
43 Effect on the Scant Displacement of Switch Rail of High - speed Turnout by the Differential Motion Device
WANG Ping, MA Xiao -chuan, WANG Jian, XU Jing -mang
Research purposes ： In order to research the effect of the differential motion device on the switching force and scant displacement of switch rail at high speed turnout, a model which could analyze the effect of differential motion device on the switching of high - speed turnout based on the finite element theory- The role of scant displacement adjustment of switch rail was analyzed. The variation of switching force and scant displacement was analyzed after the adjustment of scant displacement using the differential motion device.
Research conclusions ： (1) The effect of scant displacement adjustment using differential motion device is significant, the maximum scant displacement is decreased from 1. 64mm to 0. 49mm. (2) A total six switching process was calculated after the scant displacement adjustment of switch rail, and the scant displacement is not rebounded.After the adjustment of scant displacement, the switching force is decreased significantly for the alignment change of switch rail. (4) The adjustment effect method of scant displacement using the differential motion device is better compared with traditional methods. (5 ) The research of differential motion device can provide a good guidance for the adjustment of scant displacement in high - speed turnout.
2015 Vol. 32 (11): 43-48 [Abstract] ( 4633 ) HTML (1 KB)  PDF  (923 KB)  ( 2644 )
       Bridge Engineering
49 Effect of Traveling Wave on Elastic - plastic Seismic Response of Low - pylon Cable - stayed Bridge
LI Xiao - zhen1,LIU Zhen - jie1,LEI Hu - jun2,HONG Qin - ye1
Research purposes ： In order to research the variation of elastic - plastic seismic response of railway low - pylon cable - stayed bridge under the excitation of traveling waves， based on the theoretical foundation of elastoplastic analysis and taking a railway low - pylon cable - stayed bridge with span arrangement 144 m + 288 m + 144 m as an engineering situation, the difference of elastic - plastic seismic response of bridge under uniform excitation and wave - passage excitation ( different shear velocity had been considered ) simulated by large stiffness method was analyzed.
Research conclusions:( 1 ) The responses of elastic - plastic displacement， moment and nonlinear ductility ratio of displacement of piers are increased as well as its plastic deformation, compared with the situation of uniform excitation. When shear velocity is 200ix^s，the nonlinear ductility ratio of displacement of Fuzhou and Pingtan s side of No. 9 pier and No. 10 pier have increased by 6. 32%，17. 90%，17.67% and 33.92%，which reduces the ductility seismic capacity of piers. (3) The effect of traveling wave should not be ignored when involving the ductility seismic design of similar structures. (4) The research results can be used in guiding for ductility seismic design of bridges.
2015 Vol. 32 (11): 49-54 [Abstract] ( 2673 ) HTML (1 KB)  PDF  (780 KB)  ( 2677 )
55 Analysis of the Influence of Section Form on Local Vibration Characteristics of High - speed Railway Box Girder
LUO Wen -jun，ZHANG Xin – yuan
Research purposes ： The root cause of the structural noise of high - speed railway viaduct is the local vibration which is generated when the train passing through the bridge and the vibration frequency is between 20 ~ 200 Hz. We can know from some research it is poor to control the structural noise through the route of transmission. A more sophisticated method should be used to study the origin of the method.
 Research conclusions: Based on the vehicle - track coupling dynamics，the local vibration of the high - speed railway box girder is analyzed by the Finite Element Method ( FEM) in detailed. Six representative sensitive points were selected，and the point vibration response under various conditions was analyzed. The results show ： (1) The local vibration can be controlled effectively by changing the thickness of the top plate in the practical engineering, at the same time the form must meet other preconditions. (2) By the analysis of changing the angle of the web，the smaller inclination of the structure has a certain control effect on the local vibration. But it does not mean that it must be set to 0 degrees for controlling the local vibration. Other factors must be taken into consideration to set the most appropriate web inclination. The study results have some guiding significances for the design of vibration and noise reduction of high speed railway bridge engineering.
2015 Vol. 32 (11): 55-61 [Abstract] ( 2663 ) HTML (1 KB)  PDF  (1285 KB)  ( 2512 )
62 Research on the Influence of Bridge Slope on Uplift Force of the Fasteners at Continuous Beam Ends Hot!
TIAN Chun - xiang
Research purposes ： If ballastless track was laid on long - span bridges, the gradient，span and temperature change of bridge will have impact on force of fasteners at beam end. A finite element model which could calculate the force of fasteners on sloping bridges was established. The influences of bridge gradient， temperature variation， temperature span and the layout of fixed bearing of the adjacent simply supported beam bridge on fastener force were analyzed with the model. The maximum gradients of continuous beam bridges with different height piers and temperature spans were determined based on the fastener force under the disadvantageous load effect combination which might occur during the operation. The value could provide theoretical guidance for the design of ballastless track on long - span bridges in mountainous area.
 Research conclusions:( 1 ) The influence of the gradient of bridge on the direction of fasteners force should be considered when calculating the fastener force affected by the deformation of sloping bridge. (2) With the increasing of  gradient, the temperature variation and the temperature span, the maximum additional force of fasteners increases linearly. The configuration with the fixed bearing of simply supported bridge adjacent to the continuous beam bridge laying on the direction of foil is beneficial to the fastener. ( 3 ) In order to make sure that the fastener force does not exceed the limit value under disadvantageous load effect combination, the maximum gradients of continuous beam bridges with different height piers and temperature spans are acquired, and the laying transition slab between the ends of
two beams can increase the maximum gradients. (4) The results can be used to guide the design of bridge and ballastless track.
2015 Vol. 32 (11): 62-69 [Abstract] ( 2718 ) HTML (1 KB)  PDF  (593 KB)  ( 2657 )
70 Experimental Research on the Welding Property of Steel Box - girder at Low Temperatures
WANG Chao
Research purposes： Welding at low temperature is an unavoidable problem in the construction of steel bridge in North China, in order to solve the problem of low temperature welding in steel structure, for Q345E steel with steel box girder of a bridge in the Yalv River, the test plate was designed and fabricated. The mechanical properties of the test plate welded joints were tested by chemical composition，microstructure，tensile，hardness and low temperature impact， Reasonable welding process measures are studied，in order to ensure the quality of steel box - girder welding at low temperature.
Research conclusions:( 1 ) Test results show that the performance indexes of the welded test plate meet the requirements. (2) On the basis of the experiment, the reasonable heat preservation measures, the preheating scheme and the suitable welding technology for the welding of low temperature environment are studied. The bridge girder segment splicing welding at low temperature measures are put forward，and successfully used in the welding of steel box girder bridge， The qualified rate of the welding seam reached 100%. (3 ) The research results effectively ensure low temperature welding quality of the Yalu River Bridge steel box girder, for the vast northern region all - weather welding provides the reference for the construction.
2015 Vol. 32 (11): 70-72 [Abstract] ( 2794 ) HTML (1 KB)  PDF  (438 KB)  ( 2597 )
73 Research on the Damage Detection Method on Existing Girder Hoisting Machine
CHEN Shi - tong1, CUI Chen - guang2,LI Yi - qiang1, ZHANG Yao - hui1
Research purposes ： The structural damage of large - tonnage girder hoisting machine, such as surface corrosion，welding crack，steel crack，are difficult to detect and recognize,resulting in unnecessary engineering accident. With reference to the structural features，the ANSYS was used to set up the finite element model for the girder hoisting machine, the different level structural damage on the different structural position was analyzed. The impact of the structural damage on the dynamic characteristics and main girder deflection were researched，then the damage detection method was put forward based on the research results.
Research conclusions:(1) The change of dynamic characteristics can be used to identify the structural damage，but it can not determine the location of damage. (2) The vibration mode of the girder hoisting machine changes with the structural form，then the frequency change caused by structural damage is obvious on different vibration mode with the different structural form. ( 3 ) Based on the research results, the deflection curve of the main girder can be used to identify the structural damage and to determine the location of one - point damage and multi - point damage. (4) This research result is helpful for structure inspection test and condition assessment of existing girder hoisting machine.
2015 Vol. 32 (11): 73-79 [Abstract] ( 2746 ) HTML (1 KB)  PDF  (1108 KB)  ( 2538 )
80 Damage Identification Metliod for Benchmark Structure Based on Health Monitoring Hot!
YANG You - fa, WANG Fei - yu，XU De - jian
Research purposes ： Because the bridge structure of long - term using may be damaged by external load , environmental effect , natural calamities and human factors , its loading capability will decrease gradually , and its security has attracted more attention. Therefore , it is an imperative problem to detect bridge damages so that its security can be evaluated and monitored nowadays.
 Research conclusions：For the typical Benchmark structure , an assessment method of structural overall damage degree by using the acceleration power spectrum and principal component analysis with the Mahalanobis distance is presented.(1) The damage diagnosis method directly uses power spectrum for bridge damage identification , does not need any modal parameters and integral modal data , so damage diagnosis results are not affected by modal errors and incomplete
data. (2) The damage diagnosis , which is performed by analyzing data characteristics and data structure of power spectrum , does not need bridge mechanics mode , so it has not any special requirement for bridge structure types , restricting manner and boundary condition. (3) The dynamic test method using manual excitation and SISO is simple and convenient. (4) The damage diagnosis method proposed in the paper has very important theoretical and practical value for health monitoring and damage diagnosis of existing bridge.
2015 Vol. 32 (11): 80-86 [Abstract] ( 2802 ) HTML (1 KB)  PDF  (493 KB)  ( 2546 )
       Tunnel Engineering
87 Research on the Law and Prediction of Long - term Settlement of Shield Tunnel in Soft Soil Stratum
YANG Bing - ming
Research purposes ： Model test is one of the most important methods for studying the problem of tunnel engineering. For analyzing the key reasons of long - term settlement in soft soil stratum in Ningbo, engineering characteristics of the first line of Ningbo rail transit in soft soil stratum is considered, and long - term settlement of muddy clay and sand is effectively simulated with centrifugal model test. The effect of soil moisture content of the soft soil stratum is taken into account, whether seepage water effect on a long - term settlement of shield tunnel.
Research conclusions:(1) The moisture content of the soft soil stratum has great effect on the long - term settlement of the tunnel. The long - term settlement of the tunnel can be expressed as floating or sinking with different the moisture content. (2) The tunnel is not easy to follow a stable settlement in muddy clay stratum, but the tunnel is fast stable of the soil settlement in sand stratum when the sand stratum leaks water. ( 3 ) The centrifuge model test and the logarithmic curve method have the same value, and the logarithmic curve prediction model provides technical reference for the actual construction.
2015 Vol. 32 (11): 87-92 [Abstract] ( 2785 ) HTML (1 KB)  PDF  (960 KB)  ( 2628 )
93 Construction Control Technitjue for High Geostress Tunnel in Chongqing - Guizhou Railway
WANG Ming - hui1, ZHANG Zhong - ai2, ZHANG Qiao1
Research purposes： Tianping tunnel of Chongqing - Guizhou railway is 13. 928 km long，and is the key workpoint. The geostress conditions of Tianping tunnel is very complicated. When entering the construction of inclined shaft , the deformation of initial supports and baseboard was serious , by measuring the crustal stress , the inclined shaft was judged extreme - high geostress zone，which was apt to effect large deformation. So the problem was what reliable construction methods was adopted to safely pass the high geostress zone.
Research conclusions ： By the construction practice of Tianping tunnel, the paper summarized the following construction methods to guarantee the safety and quality of high geostress zone ： (1 ) Increase the deformation allowance to guarantee that the deformation of soft rock under high stress was not not beyond limit. (2 ) Strengthen monitoring measurement and predict the deformation of the surrounding rock to guide the construction. (3) Timely adjust support parameter and dynamically adapt the surrounding rock. (4 ) Timely cast the scondary linings,when deformation rate was continuously less than 1 mimd for seven days. (5) The research conclusion can provide references and lessons for constructions of similar high geostress tunnels.
2015 Vol. 32 (11): 93-97 [Abstract] ( 4854 ) HTML (1 KB)  PDF  (906 KB)  ( 2610 )
       Railway and Rail
98 Exploration on the Compaction Mfect of Static Pressure in Foundation of Loess Tunnel of Baoji - Lanzhou Passenger Dedicated Line
MI Wei - jun1, JIA Yun2, JIA Yan3, QU Yao - hui1
Research purposes ： There are five geomorphic units and lots of loess along Baoji - Lanzhou passenger dedicated line, with the characteristic of high collapse grade and large vulnerability of vibration with big thickness. But there are high standard and difficult vibrate - controlling about treatment of loess tunnel foundation. The geomorphic unit of Anjiazhuang loess tunnel is loess plateau and mountain ridge area , the loess around tunnel is provided with strong collapsibility , and collapsible grade of area is IV ( very serious) , besides , the dark cave foundation uses the design of piles of preformed holes which are made by static pressure.
Research conclusions: The results showed that:(1) The treatment method and equipment about static pressure , which was developed by Northwest Research Institute Co. Ltd of China Railway Engineering Corportion, suit to compaction of foundation in loess tunnel. (2) If the goal is to eliminate the collapsibility of loess between piles and make the compaction coefficient meet the specification, the suitable pile diameter and spacing hade are 0. 41 m and 0. 91 m respectively. (3) If the bearing capacity meets design requirement, the minimum coefficient of compaction and the average coefficient of compaction can be less than the specified standard , and the suitable pile diameter and spacing hade are 0. 41 m and 1.2 m respectively. (4) The research results can be directly applied to design and construct about the compaction treatment of tunnel foundation in collapsible loess, also can be used to reinforce and process foundation at collapsible loess site with narow and small space and non - vibration space.
2015 Vol. 32 (11): 98-101 [Abstract] ( 2655 ) HTML (1 KB)  PDF  (716 KB)  ( 2534 )
       Tunnel Engineering
102 Treatment Technology for Water and Mud Bursting of Deep Water Rich Sliding Type Weak Zone on Tunnel
ZHANG Min - qing1, GAO Yang2
Research purposes ： DK 96 + 505 ?DK 96 + 530 paragraph o Liangshan tunnel on Xiamen - Shenzhen Railway developed water rich granite weak zone in which the length is 25 m, buried depth is 270 m. The weak zone is steeply inclined with a dip angle of 75 degrees to 85 degrees, and the two ends are complete granite. The lateral extension length of the weak zone is about 2. 3 km. On March 14 , 2009 , when the tunnel excavated to the weak zone , water and mud bursting occurred , mud total is about 30 thousand m3 , and siltation tunnel length is 230 m , resulting in surface collapse 200 m2 and pit depth of 20 m. Then set the circuitous heading at the left side of the tunnel , water gushing occurred again in the construction , the construction was blocked. Therefore , it is necessary to study the construction technology scheme to deal with the deep water rich sliding type weak zone.
Research conclusions:(1) For deep water slide type soft with water and mud bursting , the comprehensive treatment scheme of 11 drainage and pressure lowering , grouting reinforcement , advanced pipe shed" is feasible. (2) For a large span tunnel , the 11 Gaoyang construction method" is adopted , the total deformation during construction is 2 mm , this method is safe and reliable , and the construction is relatively simple. (3) The research results can be used for the treatment of water rich sliding weak zone on tunnel.
2015 Vol. 32 (11): 102-106 [Abstract] ( 2672 ) HTML (1 KB)  PDF  (707 KB)  ( 2758 )
107 Analysis of Wear Model and Wear Characteristics of Shield Cutter Cutting Soft Rock
TAN Qing 1,ZHANG Jin - hao 1,XIA Yi - min1, ZHANG Gui - ju2, SUN Xin - jian 1,ZHANG Xu - hui 1
Research purposes: In order to study the wear characteristics of shield cutter andthe factors influencing cutter wear while cutter is cutting soft rocks , the contact force between cutter and soft rock on rake face and rear face was analyzed, and combined with the analysis of trajectory 〇f cutter, a wear model of shield cutter was established based on abrasive wear equation. The impact of cutting depth , rotate speed of cutter head , rake angle and rear angle on cutter wear were analyzed. By producing concrete simulating soft rock and using cutters of different structures , an experiment was done with the use of rotary test - bed to analyze the factors influencing cutter wear. The experiment has researched the effect of cutting depth , rotate speed of cutter head , rake angle and rear angle on cutter wear.
Research conclusions ： A wear model of shield cutter was established , the results of the study indicates ： (1 ) With the increasing of cutting depth , the contact force between cutter and soft rock increased , the effects of micro - cutting and ploughing enhanced , which resulted to the increasing of wear volume. (2) With the increasing of rake angle, the contact force on rake face between cutter and soft rock decreased , leading to the reduction of cutter wear volume. (3) With the increasing of rear angle , the contact force on rear face between cutter and soft rock decreased , leading to the reduction of cutter wear volume. ( 4 ) The rotate speed of cutter head has little influence of cutter wear volume if the cutting length remains the same. (5) The results of the expeement were consistent with the wear model , which validated the correctness of the theoretical model. (6) The research methods and results can provide reference for research and design of shield cutter.
2015 Vol. 32 (11): 107-112 [Abstract] ( 2803 ) HTML (1 KB)  PDF  (735 KB)  ( 2567 )
       
113 Research on the Parameter Optimization of Lines Connecting Main Line and Arrival - departure Line in High - speed Railway Station Yard Hot!
WEI Qing - chao1，YIN Guo - dong1,SHI Jin1, LAI Lin2
Research purposes： With numerous railway lines laid in the yard， high - speed railway station should not only meet the operation requirements of train to pass in high speed，but also satisfy the demand of high - speed train to arrival, departure and turn - back in station yard. For the influence of speed reduction of train and station arrangement， radius of curve on arrival - departure line is much less than that of curve on main line, and parameter selection of lines connecting main line and arrival - departure line affects the travel quality of train directly. Referring to existing researches，and based on the dynamic theory and wheel - rail contact mode，dynamic analysis model was established， considering the running conditions of train between the main line and the arrival - departure line in high - speed railway station yard. Using the established model, effects on travelling safety and stability of train aroused by length variation of intermediate straight line and transition line connecting turnout on main line and curve on arrival - departure line behind turnout were calculated. Accordingly， theoretical basis is provided for the parameter optimization of lines connecting arrival - departure line and main line in high - speed railway station yard.
 Research conclusions ： Based on related researches on the matching relation of superelevation and transition curve length with circular curve radius, required calculation parameters were selected, and calculations on the relation between travelling quality of train and parameter variation of connection lines between main line and arrival - departure line indicate that ： (1) To meet the demand of traveling stability, intermediate straight line with length not less than 9 m was proposed to be set to connect turnout on main line and curve on arrival - departure line in high - speed railway station yard. (2 ) The increase of transition curve length has rarely influence on easing vehicle vibration on circular curve as the length of transition curve reaches a certain value. (3) Guidance is provided to space distributionand parameter selection of lines connecting main line and arrival - departure lineinhigh - speed railway station yard, when the scale of station yard is limited.
2015 Vol. 32 (11): 113-119 [Abstract] ( 2891 ) HTML (1 KB)  PDF  (762 KB)  ( 2583 )
       Urban Rail Construction
120 Analysis of Mechanical Characteristics for Lining of Existing Metro Tunnel upper Crossing by Close Range Excavation Passageway in Loess Region
WANG Jun - qi1, KANG Zuo1, ZHAO Jie2
Research purposes ： In order to understand mechanical characteristics for lining of existing metro tunnel upper crossing by close range excavation passageway in loess region，relied on the project of m - C to n - B passageway of Taibai South Road Station of Xi an metro line No. 3, based on the field tests， this paper analyzed the contacting pressure between initial supports and secondary linings and stress of secondary linings of existing metro tunnel.
 Research conclusions ： ( 1 ) The contacting pressure between initial supports and secondary linings of existing metro tunnel in earlier crossing line on the whole is smaller than in later crossing line, and in one tunnel case the pressure on the construction surface side is greater than on the other side. (2) The contacting pressure of each monitoring point in left and right lines is increased in the construction process of upper crossing passageway， and the increase range of monitoring points in later crossing line is more than in the earlier crossing line. ( 3 ) Influenced by the change of upper crossing passageway height， the secondary linings of the earlier crossing line presents the trend twist to the left， the stress of the left side is pressure stress and the right side is first pulling stress after to pressure stress. (4) The stress of scondary linings of later crossing line is basically symmetrical，which on the whole is larger than the earlier crossing   line. (5)The research results can provide reference for the design and construction of similar engineering in loess region.
2015 Vol. 32 (11): 120-127 [Abstract] ( 2684 ) HTML (1 KB)  PDF  (1461 KB)  ( 2628 )
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