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Shi Y.,Beijing Jiaotong University | Shi Y.,Suzhou Rail Transit Group Co. | Zhang W.,Nanjing University | Sun K.,Nanjing University | And 2 more authors.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2017

The measurement of weak ambient acceleration responses, induced by subway train vibrations, needs an accuracy of mg scale, which could not be easily satisfied using ordinary on-board MEMS accelerometers. In the paper, by using the low-noise OP-Amp OPA4344 and ADC Q4FA512, the measurement range of the MEMS accelerometer SD1221L-002 was limited in ±0.2 g, so as to accomplish an acceleration resolution of 0.043 mg to satisfy the testing requirement of weak ambient vibrations. A specific wireless sensor network system was developed for the testing of subway train induced ambient accelerations. The system was based on Intel Imote2 wireless sensor network platform, combined with the embedded software platform ISHMP Services Toolsuite. Based on the open-source operation system TinyOS, the component structural programming language nesC was used to program the embedded application component VibrationLevelCalculation, so as to embeddedly compute the ambient vibration level. The system was used to measure the ambient vibration responses induced by subway train vibrations of an underground space adjoining the subway station. The ambient acceleration signals were acquired at the sensor nodes the vibration levels were embeddedly computed in the Imote2 main board of the sensor board, and the distribution of the ambient vibration level was directly displayed on the terminal. In addition, the one-third octave bands spectra at measuring points were obtained by retrieving the vibration level data at the center frequencies stored inside the sensor nodes. The developed system implements the fast assessment of the ambient responses induced by subway train vibrations. © 2017, Editorial Office of Journal of Vibration and Shock. All right reserved.


Cheng Y.,Nanjing Southeast University | Cheng Y.,Suzhou Rail Transit Group Co. | Liu S.-Y.,Nanjing Southeast University | Liu S.-Y.,Suzhou Rail Transit Group Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2013

The resonant vibro-compaction is a new ground improvement method for liquefaction sites. On the basis of the review of the reinforcement mechanism of the resonant vibro-compaction, a crisscross section vibratory probe and the relevant construction equipments are developed by the authors. The application of the deep resonant vibro-compaction in the ground treatment of silty liquefiable site is presented. Comparative tests including the piezocone penetration test, shear wave velocity measurement and standard penetration test before and after improvement are conducted to assess the liquefiaction resistance, and the economic efficiency of the resonant vibro-compaction is compared with that of the replacement stone column and dynamic compaction. It is shown that the resonant vibro-compaction is an effective way for liquefaction mitigation, and it has good economic efficiency.


Cheng Y.,Tongji University | Cheng Y.,Suzhou Rail Transit Group Co. | Liu S.-Y.,Nanjing Southeast University | Zhu H.-H.,Tongji University | And 3 more authors.
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2016

Field tests on silty foundation reinforcement were conducted to research variation of excess pore pressure during vibration construction process by using crisscross section vibration probe compaction method. And ground influence range by vibration and reinforcement effectiveness by the method were compared with those by Swedish vibro-wing. The main factors influencing compaction effect such as space between vibration points, exciting force and style of vibratory probe were analyzed. The results show that re-driving technique and load time have little impact on compaction effect. Radial radius of foundation reinforcement for single vibration point is 1.2-2.7 m. Safety distance of construction by crisscross section vibratory probe is more than 2m, which is prior to that of vibro-wing. The effect of compaction overlying at small space between vibration points is obvious. Soil uniformity can be improved by appropriately increasing exciting force. Crisscross section vibratory probe is designed with cutouts, which increases contact with soils and amplitude improvement is beneficial for energy transfer. © 2016, Editorial Department of China Journal of Highway and Transport. All right reserved.


Chen H.,Beijing Jiaotong University | Chen H.,Suzhou Rail Transit Group Co. | Yuan D.,Beijing Jiaotong University | Wang F.,Suzhou Rail Transit Group Co. | Wang M.,Beijing Jiaotong University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2016

Based on the construction of shield cutting of 14 big diameter bridge piles in Suzhou subway, the variation characteristics and influence factors of cutting parameters are studied systematically by theoretical analysis and the field test of shield cutting Φ1200 reinforced concrete piles. Corresponding setting and control method of cutting parameters is proposed. The research results show that actual cutting number has obvious fluctuation because of non full-face cutting feature of cutterhead cutting pile, and actual cutting number is the main influence factor of variation characteristics of thrust and torque. The average value of thrust and torque is directly proportional to pile width, and the thrust and torque decrease generally when pile offset distance increases. Due to the great fluctuation amplitude of advancing speed, thrust and torque, a hydraulic pump of small flow should be configured in addition. The thrust and torque acting on the pile are approximately linear with the cutterhead penetration. The Suzhou engineering practice indicates that it is feasible for shield to cut big-diameter reinforced concrete piles continuously when the cutting parameters are resonable. © 2016, Editorial Office of China Civil Engineering Journal. All right reserved.


Chen H.,Beijing Jiaotong University | Chen H.,Suzhou Rail Transit Group Co. | Yuan D.,Beijing Jiaotong University | Wang F.,Suzhou Rail Transit Group Co. | Wang M.,Beijing Jiaotong University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2015

Based on the construction of shield underpassing Shanghai-Nanjing intercity high-speed railway in Suzhou rail transit line 2, the risk of shield underpassing high-speed railway was analyzed systematically and a set of risk control system including various measures was proposed by theoretical analysis and three dimensional numerical simulation. The research results show that post-construction settlement should be given full consideration when making settlement control standard. Due to the fact that traditional solution of just grouting reinforcement can' t meet the need of crossing through high-speed railway, the new protection system of plank-pile structure with partition grouting was put forward. The train running speed should be limited during underpassing construction period, excellent shield equipment, tunneling technology of small perturbations, fully synchronous and secondary grouting and automatic remote monitoring can effectively avoid or reduce the construction risk of underpassing high-speed railway. The safety and smoothly of practical engineering illustrates the rationality and validity of the shield crossing through high-speed railway control measures proposed by the paper. ©, 2015, Editorial Office of China Civil Engineering Journal. All right reserved.

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