scholarly journals A Case Study on Stratified Settlement and Rebound Characteristics due to Dewatering in Shanghai Subway Station

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Jianxiu Wang ◽  
Tianrong Huang ◽  
Dongchang Sui
Keyword(s):  
Soft Clay ◽  
Subway Station ◽  
Silty Clay ◽  
Metro Station ◽  
Absolute Value ◽  
Sandy Clay ◽  
Centrifugal Model ◽  
Shanghai Metro ◽  
Different Soils

Based on the Yishan Metro Station Project of Shanghai Metro Line number 9, a centrifugal model test was conducted to investigate the behavior of stratified settlement and rebound (SSR) of Shanghai soft clay caused by dewatering in deep subway station pit. The soil model was composed of three layers, and the dewatering process was simulated by self-invention of decompressing devise. The results indicate that SSR occurs when the decompression was carried out, and only negative rebound was found in sandy clay, but both positive and negative rebound occurred in the silty clay, and the absolute value of rebound in sandy clay was larger than in silty clay, and the mechanism of SSR was discussed with mechanical sandwich model, and it was found that the load and cohesive force of different soils was the main source of different responses when decompressed.

scholarly journals The use of Geoeletric Methods for Post-foundation Assessments of Distressed Buildings in Ebute-meta, Mainland Local Government Area of Lagos State

2021 ◽  
pp. 104-119
Author(s):  
O. J. Airen
Keyword(s):  
Soft Clay ◽  
Maximum Depth ◽  
Silty Sand ◽  
Silty Clay ◽  
Clayey Sand ◽  
Near Surface ◽  
Cone Resistance ◽  
Sandy Clay ◽  
Geotechnical Investigations ◽  
Support Engineering

Geophysical and geotechnical investigations were combined to investigate the immediate causes of the distresses and foundation failures of buildings in Ebute-Meta area of Lagos, south-west Nigeria. Six (6) traverses were mapped in the study area across which six (6) 2D Wenner ERI, and fourteen (14) VES geophysical data were acquired. One (1) boring and five (5) CPT geotechnical data were also acquired. 2D ERI results reveal that resistivity values vary from 4.62 – 293 Ωm across the study area. Three resistivity structures were identified which denoted peat/clay, sandy clay, clayey sand and sand. The resistivity of the peat/clay varies from 4.62 – 27.9 Ωm with thickness varying from 12 - 25 m. The sandy clay varies in resistivity and thickness values from 26 – 86 Ωm and 8 – 29 m respectively. The clayey sand from 84.4 – 182 Ωm and 10 -15 m, and sand, having resistivity and thickness values of 293 Ωm and 3 – 5 m. The VES reveals similar results to the 2D ERI, delineating six geoelectric layers which are the topsoil, peat, clay, sandy clay, clayey sand and sand at maximum depth of 35.8 m. The borehole (BH) reveals a maximum boring depth of 45 m with eight zones comprising dark grey sandy clay, firm to stiff silty clay, soft, dark organic silty peaty clay, grey silty sand, dark grey silty sandy clay, dark grey organic peaty clay, grey silty sandy clay and medium dense to dense grey sand with occasional gravels. The CPT, which penetrated a maximum depth 15.8 m reveal that the cone resistance values vary progressively from 0 – 162 kg/cm2indicating very soft clay to soft clay near-surface and medium dense to dense geologic material at deeper depth. The peat/clay delineated by the 2D ERI and VES at 5 – 25 m depth with resistivity value varying from 4.62 -17 Ωm in the study area, and also revealed in the BH at 5.75 – 27.75 m depth as soft, dark organic silty peaty clay, having cone resistance values varying from 0 – 20 kg/cm2 is laterally extensive and incompetent to support engineering foundation.

scholarly journals A Queuing Network Based Optimization Model for Calculating Capacity of Subway Station

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Hanchuan Pan ◽  
Zhigang Liu
Keyword(s):  
Optimization Model ◽  
Subway Station ◽  
Queuing Model ◽  
Selection Probability ◽  
Evaluation Indexes ◽  
State Dependent ◽  
Decision Variables ◽  
Proposed Model ◽  
Shanghai Metro

Capacity of subway station is an important factor to ensure the safety and improve the transportation efficiency. In this paper, based on the M/G/C/C state-dependent queuing model, a probabilistic selection optimization model is proposed to assess the capacity of the station. The goal of the model is to maximize the output rate of the station, and the decision variables of the model are the selection results of the passengers. Finally, this paper takes a subway station of Shanghai Metro as a case study and calculates the optimal selection probability. The proposed model could be used to analyze the average waiting time, congestion probability, and other evaluation indexes; at the same time, it verifies the validity and practicability of the model.

scholarly journals Case study on the seismic response of a subway station combined with a flyover

2021 ◽  
Author(s):  
Qi Wang ◽  
Ping Geng ◽  
Xiangyu Guo ◽  
Xinqiang Wang ◽  
Peisong Li ◽  
...  
Keyword(s):  
Seismic Response ◽  
Subway Station

scholarly journals Understanding the integration of buses and metro systems using smart card data

2019 ◽  
Vol 2 ◽  
pp. 1-6
Author(s):  
Diao Lin ◽  
Ruoxin Zhu
Keyword(s):  
Smart Card ◽  
Public Transportation ◽  
Pearson Correlation ◽  
Metro Station ◽  
Smart Card Data ◽  
Pearson Correlation Test ◽  
Metro Systems ◽  
The City ◽  
Afternoon Peak

<p><strong>Abstract.</strong> Buses are considered as an important type of feeder model for urban metro systems. It is important to understand the integration of buses and metro systems for promoting public transportation. Using smart card data generated by automatic fare collection systems, we aim at exploring the characteristics of bus-and-metro integration. Taking Shanghai as a case study, we first introduced a rule-based method to extract metro trips and bus-and-metro trips from the raw smart card records. Based on the identified trips, we conducted three analyses to explore the characteristics of bus-and-metro integration. The first analysis showed that 46% users have at least two times of using buses to access metro stations during five weekdays. By combining the ridership of metro and bus-and-metro, the second analysis examined how the share of buses as the feeder mode change across space and time. Results showed that the share of buses as the feeder mode in morning peak hours is much larger than in afternoon peak hours, and metro stations away from the city center tend to have a larger share. Pearson correlation test was employed in the third analysis to explore the factors associated with the ratios of bus-and-metro trips. The metro station density and access metro duration are positively associated with the ratios. The number of bus lines around 100&amp;thinsp;m to 400&amp;thinsp;m of metro stations all showed a negative association, and the coefficient for 200&amp;thinsp;m is the largest. In addition, the temporal differences of the coefficients also suggest the importance of a factor might change with respect to different times. These results enhanced our understanding of the integration of buses and metro systems.</p>

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