Papers by Keyword: Foundation Pit

Abstract: This paper deals with the construction of the foundation pit of the East Station of Meixi Lake, belonging to Reme Area underground supporting transport system of Changsha, China. A description is given of the deformation monitoring of the open excavation. During site operations, the construction process monitoring data are continuously analyzed. It has been found that the deformations induced by the excavation of the foundation pit have some influence on the surrounding buildings. Monitoring of both horizontal pile-top displacement and ground surface settlements are extremely important to ensure safety of the neighboring constructions. Based on the monitoring information gathered during construction, engineers should adjust construction parameters to optimize the design at any moment, and adopt effective treatment measures to ensure the follow-up constructions can safely and successfully complete.

Abstract: Concrete diaphragm wall is widely used in deep foundation pit projects in city. Its lateral deformation is an important item in the deformation monitoring of the retaining structure of foundation pit. Traditional monitoring techniques for concrete diaphragm wall deformation collect data only from several sections, failing to understand the overall foundation pit deformation. Taking the north pit of Huaihai road station on Shanghai Metro Line 13 as an example, this study measures overall deformation by means of terrestrial laser scanning. Methods of data collection and data process will be introduced. A three-dimensional modeling algorithm using point cloud data of foundation pit is proposed so that the overall model of the concrete diaphragm wall can be got. And finally the overall deformation can be got by comparing the model of different periods.

Abstract: On the basis of ground geology and hydrogeology of an urban river, a municipal tunnel in which public pipes and cables are placed is designed to cross the river by means of open cut method. The main structure of the municipal tunnel and its waterproof measures are both summarized in this paper. Reinforced concrete frame structure with one story and three box-shaped sections is used in the design of the municipal tunnel. Both self-waterproof structure and waterproof sheet are applied to prevent ground water from permeating into the subaqueous tunnel. The installation of public cables and pipes are still elucidated in the paper. The typical structure of the municipal tunnel can be a guiding reference for the design of other subaqueous tunnel to cross urban rivers under analogous conditions.

Abstract: In order to study the vertical displacement distribution of foundation pit in the process of step-by-step excavation, combined with a foundation pit project, numerical simulation analysis with finite element software was carried in the research. The results show that: in the process of excavation, the maximum settlement of soil outside the pit is 41.4 mm, which is 2.95 ‰ of pit excavation depth and conforms to the recommended value in specifications. The maximum vertical displacement of soil at the bottom of foundation pit is in the center of pit. Its value is gradually increasing with the excavation, and the maximum is 60.1 mm, which is 4.32 ‰ of foundation pit depth,also,it conforms to the specifications proposed value. The proposed scheme can satisfy the vertical displacement of foundation pit excavation in the construction process.

Abstract: Based on the introduction of the characteristics of the supporting project of a large building foundation pit, the paper analyzed the main reasons for side wall collapse and pile fracture, including leakage water in the backfill soil, complex geological environment and unreasonable soil pressure value, low safety factor and improper design parameters, and then respectively proposed three kinds of treatment schemes for side wall sliding and pile breaking, landslides and other dangers. Finally, tracking observation showed that the satisfactory effect can strongly verify the suitability and validity of the main control parameters for the deformation of deep foundation pit, which may provide reference for the design and construction of similar projects.

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.

Abstract: In geotechnical engineering, the support pattern regularly applied is continuous wall, whose high security, strong adaptability, good stability and other characteristics have been widely appraised in engineering circles. This paper use Midas to build the three-dimensional research model on varied construction stages of foundation pit, in which the foundation pit applies the scheme of combing continous wall and inner support. Further more, this paper makes estimation on the machenical stability in varied construction stages of foundation pit and use strength deduction method to analyze the stress and strain conditions of foundation pit in different working states, the results acquired from which researches have certain reference to the engineers.

Abstract: Due to the existence of underground building, the distribution of displacement field of adjacent foundation pit is obviously different from that of general foundation pit, and it is of great significance to correctly understand the sheltering effect of underground building to displacement field for determining the protection class of foundation pit while supporting design of foundation pit, and protecting the safety of metro station built near and surrounding buildings during the construction. Relying on the foundation pit project of metro station and combining the sensitivity theory through mechanism analysis, this article discovers that the sheltering effect is most obvious when the spacing between the underground building and retaining wall of foundation pit is 0.5H, and the sheltering effect can be ignored when the distance is more than 2H.

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.

Abstract: Based on the analysis of the engineering geology and the hydrology data of a large construction project along the river in Hunan province, according to the engineering design requirements and the local construction conditions, the paper analyzed in-depth on deep excavation, groundwater control and high slope treatment schemes. The results can provide a reference for similar engineering problems.