| With the rapid development of economy and the acceleration of urbanization,limited land resources are increasingly difficult to meet the needs of people's demand for land resources.Therefore,People gradually moved their eyes of developing coastal areas to make land resources.The expansion of land by artificial reclamation led to the advance of the coastline.Besides,there are also some coastal cities are limited with the pressures such as construction of the total amount Co.and economic development factors etc.and have moved their eyes to open up new land along the coast.However,the particularity of the geological conditions in the reclamation area has increased the difficulty of the construction of underground engineering.In order to ensure the construction quality and safety in the construction process,we must combine the field engineering practice to formulate and select the feasible construction plan.It is very important to select the appropriate method of foundation pit support and using reasonable method,achieve the purpose of reducing the cost as much as possible under the premise of ensuring the reasonable design and construction.This paper collects and arranges the relevant data of the foundation pit supporting method in the domestic and international offshore backfilling area,and has referenced Dalian city adjacent to the sea filling area of geotechnical investigation data,summarized the supporting method of the foundation pit of the adjacent sea filling area.This paper chose the foundation pit supporting project district in Dalian City as the research object(The bottom elevation of foundation pit is considered by-6.50 m,The elevation of foundation pit is 4.00 m,The depth of foundation pit is 10.50m).In order to select the most suitable supporting method,With the cooperation of relevant units,we have completed a series of work such as the drilling sampling,soil reinforcement,in-situ direct shear test,pumping,water quality analysis test and the experimental study on mechanical properties of rock and soil in the proposed site.A large number of experimental data obtained by field and laboratory tests were corrected and analyzed to obtain the effective parameters of rock and soil.After repeated calculation and comparison,combined with the underground water is abundant if it is the adjacent sea backfill area and connected with sea water,the space is limited.The backfill area has objective condition of weak soil mass and taking into account that the specific construction process of underground continuous wall construction equipment in the north especially in the Dalian area is not applicable.The proposed underground structure is more complex and technical means of internal cost factors.Define the assumptions' condition of each method,the accuracy of the calculation process and results.Finally,the assessment results were compared and put forward the method to improve the backfill soil as the core of the weak,choosing to use the combination of double row cantilever pile + cut slope + shotcrete + soil reinforcement as the supporting structure.The secant pile(The supporting pile and the water retaining pile are mutually occluding to form a closed curtain)as the main sealing system,at the same time by using the method of open drainage discharged catchment pit water infiltration and the side wall water leakage memory.The whole foundation pit supporting method is improved on the basis of inheriting the traditional technology,it not only can meet the safety support effect but also can set aside for subsequent foundation construction of sufficient working space.This paper overcomes the problems of increasing the complex supporting structure due to the lack of the parameters of rock and soil in the adjacent area.Secant pile is played a multiple effect,compared with the previous similar foundation pit supporting method,the method described in this paper is more safe and economic,It is especially suitable for the foundation pit engineering of the adjacent sea filling area in the north of china. |
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