Papers by Keyword: Foundation Pit

Paper TitlePage

Authors: Shi Lun Feng, Qing Qing Guo, Yong Hong Wu
Abstract: Temporary bracing is often viewed as an unnecessary step in the process of constructing a structural facility. Unfortunately, many times this often-neglected step becomes the subject of avoidable litigation and lawsuits. This paper presents a remedy case of a deep foundation pit during the construction of the bracing system located at the business center in HePing district, TianJin. Through frequent inspection and suitable countermeasures, the potential disaster was mitigated in time. There were some lessons learned from this case history.
Authors: Hui Hu, Lian Sheng Tang, Xing Li Lin, Fei Kuang
Abstract: Factors affecting the supporting structure in a soft soil foundation pit are analyzed in this paper. Based on the information obtained from accident investigation, design factors and construction factors, such as insufficient embedded depth of pile and insufficient anchor pullout resistance, are discussed in detail. The analysis and conclusions can serve as a good reference for similar projects design and construction.
Authors: Zheng Sheng Zou, Xin Liu, Wen Qing Zhang, Qing Hua Kong
Abstract: Generally, it is difficult to control the trench stability and panel joint permeability in the construction of a diaphragm wall. The high construction cost is inevitable because of the environmental pollution due to the slurry, waste of water consumption, and debris disposal treatment. A new technique, called the dry trenching diaphragm wall with self-guided double-rectangular-casing, is thereafter developed in the current study to avoid these problems. In this technique, two pieces of rectangular steel casing are driven in sequence and guided each other. The trench is made by squeezing into the soft soil. The panel alignment and straightness are assured without any joints due to the dry concrete pouring instead of the influences of the slurry. Compared to the regular diaphragm wall, the technique is an environment-friendly, less emissive and energy-conserved one by eliminating the slurry pollution with the low cost. It shows that the quality of panel connection is reliable, and the permeation-proof performance is superior with high efficiency in wall-forming due to non-joint interlocking.
Authors: Jin Long Liu, Jie Qun Liu
Abstract: In traditional calculation method, the critical thick of water-resisting layer at foundation pit can be got by comparing the gravity of water-resisting layer and water pressure of artesian aquifer, which had not considered the influence of shear strength of soil. The result of traditional calculation method is conservative to reality. Based on force equilibrium analysis of water-resisting layer, equations for calculating safety factor of abrupt gush and critical thick of water-resisting layer is suggested in this article, which considered the influence of shear strength of soil. Some cases have been studied with those new equations. It had been found that the result of those new equations is coincident with realities. In order to ensure the security of foundation pit, it is advised that foundation pit can be adjudged safety only both the safety factor of abrupt gush and critical thick of water-resisting layer satisfied requirements.
Authors: Rong Hua Ye, Gan Bin Liu, Jun Neng Ye
Abstract: The foundation pit of Fuqing road station is the first one to be excavated in Ningbo urban rail transit project. To ensure the safety of the foundation pit, a detailed monitoring scheme is established according to the engineering geological condition and design scheme of foundation pit. Due to Ningbo city is located in the classical soft clay area, there may occur pre-warning and dangerous condition during the excavation. Therefore, reinforcement of structure and soil is executed from the aspects of designing, construction, supervision and monitoring. At last, the deformation of foundation pit is controlled and the construction safety is ascertained. Furthermore, the information construction is adopted during the excavation and many data are obtained during the process of monitoring, the displacement of diaphragm wall, ground settlement and axial force of the support are analyzed. In addition, the control measures are presented and can provide reference to the future construction of the other stations.
Authors: Gong Zhang, Dao Xiang Wu
Abstract: Expansive soil has the characteristics of strong swell-shrink, developing fissures and over consolidation. This kind of soil soaking into water, which leads to its volume expansion, strength reduction but compressibility decreasing make its engineering geology properties worsen. The distribution of expansive soil in Hefei is very wide, there are more pit accidents in Hefei district in recent years. Causing the accident is mainly due to the ignorance of the characteristics and damage of expansive soil. According to many years engaged in related working experience, this paper analyses two common types of damage in foundation pit accidents. Finally, throughout the analysis of several accidents, corresponding prevention measures and construction improvement scheme have been put forward.
Authors: Lan Yao, Li Yu, Hui Wang
Abstract: The paper based on a foundation pit with pile-strut-anchor supporting structure in order to analyze the deformation of the pit. With the aid of finite element method the curves of relationship between horizontal displacement of pile body and depth, the relationship between horizontal displacement of soil adjacent to excavation and time were obtained. And then the law of change was summed. The maximal displacement appeared on upper part of the pile or turned up on the top but incremental displacement became small. The deformation of soil adjacent to excavation was directly related to the stage of excavation and had the characteristics of phase change. Through comparative analysis the result of finite element method simulation was in conformity with monitoring results. Therefore we can claim that this calculating model is appropriate and supporting structure is safe.
Authors: Yan Chao Ma, Ying Hui Chen, Yan Lian Pan, Shuai Wang, Qing Shui Liu
Abstract: Cantilever retaining structure is often applied to shallow foundation pit supporting, but it causes large deformation in soft soil region. Reinforcement of soil can solve this problem, and a finite element model of foundation pit which based on elastic fulcrum method is founded to research the regular pattern how the depth and degree of soil reinforcement effects the deformation and the inner force of the cantilever retaining structure. The result shows that the lateral deformation reduces with the increases of the depth and degree of soil reinforcement, and critical depth and degree of reinforcement can been founded. The change of inner force caused by depth and degree of soil reinforcementis small. So it is important to reasonably decide the depth and degree of soil reinforcement.
Authors: Yu Qin Feng, Chen Xi Liu
Abstract: This paper analyzes an engineering in an area of China which was processed by vacuum preloading technology in the silt soft soil. This engineering was used rigid supporting structure technology of piles in row and bolts for large area of deep foundation pit supporting. It compared the realistic measure soil pressure and theoretical concluded soil pressure, and got the soil pressure distribution mode which is suitable for silt soft soil processed in this way. The conclusion can provide a reference for similar supporting structure system to calculate earth pressure.
Authors: Shan Shan Xu, Wei Wei Li
Abstract: This paper introduces the finite element method theory of foundation pit excavation, on the basis of summarizing the past experience, combined with the mechanical property of engineered soil, by using a variety of contact relation provided by the finite element software, select the appropriate unit to simulate the foundation pit excavation model scientific and reasonable. It has a very important guiding significance in practical engineering.
Showing 1 to 10 of 67 Paper Titles