Shen J.,East China Architecture Design and Research Institute Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012
Yujiabu group excavations cover a huge plan area and meet the problem of interaction among various projects. Different excavation sequences of the group excavations are simulated by means of 3D numerical model. The results show that the superimposed ground settlement occurs among the nearby excavations caused by their excavation, and the distribution of support axial stress is influenced. Some suggestions for excavation sequence and support system and construction control measures are proposed according to the calculated results and analyses.
Tan Y.-W.,East China Architecture Design and Research Institute Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014
In the light of geological conditions of Nanchang Greenland Center Plaza, staged implementation of partitioned neighboring excavations and impact on the surrounding environment, some key technologies are described, such as the constant thickness steel cement-soil wall constructed by TRD (trench cutting re-mixing deep wall) method. The general scheme for D area, that is, the 'center island' method and the combination of various support systems is introduced. The design method for excavation engineering with the combination of various supporting systems under complex environment is discussed.
Zhang Z.,University of Shanghai for Science and Technology |
Zhang Z.,China University of Mining and Technology |
Zhang Z.,Tongji University |
Huang M.,Tongji University |
Wang W.,East China Architecture Design and Research Institute Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013
Ground settlements and underground structure deformation induced by subway tunneling are hot issues in the underground transportation construction safety control and risk assessments. Previous researches on ground settlements are basically concentrated on the soil free displacements, and the sheltering effects of adjacent existing underground structures are not considered. Based on the Shanghai tunneling case, the ground settlement rules induced by earth pressure balance (EPB) shield considering sheltering effects of tunnels in service are presented by using simplified analytical method, 3D finite element (FE) numerical simulation method, and in-situ monitoring method. An in-depth analysis is conducted between ground settlements considering sheltering effects and those considering free soil displacements. In addition, the predicted deformation of subway tunnel induced by EPB shield during complex overlapped traversing process is also presented. It is observed that the simplified analytical method and 3D finite element method can perfectly simulate the ground movements induced by subway shield excavation considering sheltering overlapped effects. Furthermore, the sheltering effects have a major influence on ground settlements induced by EPB shield when the tunnels are excavated in the vicinity of existing buildings and structures. The differences compared with the results considering free soil displacements are obtained. Finally, the deformation controlling technical measures considering sheltering overlapped effects are proposed in combination of in-situ monitoring data. It may provide certain basis to build up correctly protective measures of geotechnical environments influenced by subway tunneling, especially the sites adjacent to existing buildings and structures.
Wang W.-D.,East China Architecture Design and Research Institute Co. |
Wu J.-B.,East China Architecture Design and Research Institute Co. |
Wang X.-J.,East China Architecture Design and Research Institute Co. |
Huang M.-S.,Tongji University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011
Compared to the usual bored uplift piles, the side-grouting bored uplift piles are more effective in providing the uplift resistance by changing the interface property between the pile and the soil. The main features of the side-grouting system, construction technology and pile parameters are presented. Based on the full-scale tests, centrifugal model tests and shear tests, comparisons among the side-grouting uplift piles, base-enlarged uplift pile and straight shaft uplift pile are carried out. Some initial acknowledgement is attained, such as the bearing capacity, characteristics of load-displacement relation, interface mechanics between the pile and the soil and the strengthening mechanism of grouting. According to the engineering practice, two methods to calculate the bearing capacity of the side-grouting uplift piles are introduced, that is, grouting-strengthening empirical method and load-transfer method. The application cases of the side-grouting uplift piles in Shanghai EXPO 500 kv underground transformer substation and the project of Baiyulan Square are introduced.
Wang W.,East China Architecture Design and Research Institute Co. |
Wu J.,East China Architecture Design and Research Institute Co.
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2010
The development of underground space has the tendency of more depth. Shanghai World Exposition 500 kV underground substation has the architectural diameter of 130 meters and buried depth of 34 meters. The cast-in-place pile with the depth of 82.3 meters was used to resist water buoyancy. After subtracting the excavation depth of 34 meters, the pile length was about 48.3 meters. At the soft soil area, the piles were constructed on ground, and the test of uplift bearing capacity of the test piles which was longer than actual piles were carried out on ground. This brought out the key issue of how to analyze and design the uplift pile to reflect the influence of the deep excavation. Analyses were focused on the loss of side friction of the uplift piles in the excavated segment, the bearing capacity reduction of uplift piles because of the off-loading of excavation which lead to the pressure loss of soil around the piles, and the tension axial force of piles caused by the foundation rebound after the excavation. It was found that the bearing capacities of the uplift piles were reduced evidently and tension stresses appeared in the middle and lower part of the pile shafts due to unloading. A discount of the bearing capacities of the uplift piles was adopted in the design stage considering the decrease of bearing capacities of uplift piles due to unloading. The quantity of reinforcement of the uplift pile was checked by the sum of the axial force caused by the uplift load at the service stage and that caused by unloading at the excavation stage.