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Wei Q.,Southwest Jiaotong University | Wei Q.,Beijing Shanghai High Speed Railway Co. | Zhao G.-T.,China Railway Corporation | Cai X.-P.,Beijing Jiaotong University
Tiedao Xuebao/Journal of the China Railway Society | Year: 2013

For Slab Track CRTS II, the anchorage structure behind the abutment is used, which consists of the friction plate and main end spur. In this paper the acting mechanism of the anchorage structure was analyzed, the friction force between the friction plate and bottom slab and the resistance force of soil mass were pointed out to be the main factors to keep the anchorage structure stable, and two types of buckling forms of the anchorage structure were put forward. The method for calculating resistance forces of the anchorage structure behind the abutment was presented. The formula for calculating resistance forces of soil mass in its general state, ultimate shear state and cohesion loss state was given. By utilizing the above calculation methods, the stability of the anchorage structure with the inverted T type main end spur was analyzed and the defect with the decrease of the elastic modulus of bottom slab was pointed out. Field tests verify safety and stability of the commonly used anchorage structure with the inverted T type main end spur under designed loads and point out the direction of design optimization and disadvantage of filler.

Liu J.-F.,Southwest Jiaotong University | Zhao G.-T.,Southwest Jiaotong University | Zhao G.-T.,Beijing Shanghai High Speed Railway Co. | Ma J.-L.,Southwest Jiaotong University
Tiedao Xuebao/Journal of the China Railway Society | Year: 2011

The soil arch in the fill on the composite pile-net foundations plays an important role in pile-soil stress adjusting and settlement control. On the basis of comparison with the existing calculation methods for soil arching effect of composite pile-net foundations, the conformation of soil arch is analyzed by single-pile numerical simulation and algebraic analysis. The analytical results show as follows: The principal stress trajectory of soil arch on pile top is a group of curves whose curvatures are growing gradually in the way from the pile top plane and in the upward direction; the principal stress trajectory near the margin of the pile cap is almost the same with the shape of a parabola which decides the height of the soil arch; the height of the soil arch is related to the friction angle of fill, the bigger the friction angle is, the higher the soil arch becomes; usually, the height of the soil arch equals to the maximum inter-pile distance. The small hole expansion theory model and parabolic arch model methods are put foward to calculate the pile-ptop pressure and the inter-pile soil pressure. The calculated results accord with the results measured on site.

Zhang J.,Beijing Jiaotong University | Yang N.,Beijing Jiaotong University | Zheng X.-K.,Beijing Jiaotong University | Luan T.,Beijing Shanghai High Speed Railway Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

It is necessary to predict aerodynamic loads on buildings near tracks during high-speed train passage in order to design these buildings and determine their limits. An over-line bridge is a typical building near tracks, the train-induced flow and its aerodynamic effects on the bridge surface can not be ignored. Based on the wind pressure measurement test data of an over-line bridge, the measured wind pressure was transformed with wavelet transformation. The surface wind pressure fluctuation characteristics were analyzed and the wind pressure distribution in different frequency bands was identified. Analysis showed that the surface wind pressure components in lower frequency bands are larger, while those in higher frequency bands are smaller; the wind pressure energy in lower frequency bands is larger and that in higher frequency bands is smaller; the lower frequency part of the wind pressure has a larger impact on the bridge, while the higher frequency part has a smaller impact. Wavelet analysis was helpful to the study on surface wind pressure of the over-line bridge, its analysis and application techniques were worth further investigating. ©, 2015, Chinese Vibration Engineering Society. All right reserved.

Qiu K.,Nanjing Southeast University | Chen H.,Nanjing Southeast University | Sun W.,Nanjing Southeast University | Sun L.,Nanjing Southeast University | And 2 more authors.
Journal of Materials in Civil Engineering | Year: 2014

To determine the mechanical properties of cement asphalt mortar (CAM) in the field, this contribution first presents a model to elaborate the relationship of strength to ultrasonic pulse velocity (UPV). Next, a mechanical test (compressive, flexural strength, and static modulus) and a UPV test are conducted on CAM at different ages to calibrate the proposed model. Finally, three fitted formulas are established based on the proposed model and verified with additional test results. Results suggest that a UPV test is a helpful method for estimating the mechanical properties of CAM in the field and can reach a high precision. © 2014 American Society of Civil Engineers.

Zou L.,Southwest Jiaotong University | Wu X.,Southwest Jiaotong University | Ma J.,Southwest Jiaotong University | Peng S.,Beijing Shanghai High Speed Railway Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2010

Beijing-Shanghai high-speed railway field tests on post grouting of pile group foundation have been carried out. By analyzing the long-term settlement measured data of post grouting and non-grouting pile group foundation, the settlement development laws of post grouting and non-grouting long pile group foundation in deep soft soil have been researched. The stable time of settlement of pile group foundation are analyzed, and the influence mechanism of the post grouting effect on pile group settlement and its development laws are discussed. The conclusions are that both pile shaft grouting and pile end grouting have obvious function on the control of the settlement of long pile group foundation in deep soft soil; and the control effect of pile end grouting is superior to pile shaft grouting. For shortening time of consolidation settlement, the effect of pile end grouting is more stable. The development laws of settlement of all shaft grouting and end grouting pile group foundation have been changed obviously. Compared with corner pile grouting and side pile grouting, all pile group grouting is more beneficial to control the settlement and accelerate settlement stabilization.

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