The Cofferdam Slope Displacement Monitoring And The Reinforcement Scheme Research In Reclamation Project In Shenzhen

The stability of the cofferdam in the reclamation project is affected by soft foundation treatment backfill construction and water level fluctuation.When a new marine industrial base project in Shenzhen was implemented,the cofferdam slope was unstable.How to do the project reinforcement and make it effective and control the construction cost,construction period and efficiency became the first technical problem of the construction.Based on this background,this paper studies the displacement monitoring and reinforcement scheme of the cofferdam slope of the land reclamation project in Shenzhen.Firstly,various commonly used slope analysis methods,strength reduction methods and their respective advantages and disadvantages were analyzed.Based on a series of indoor and outdoor geotechnical tests and site survey and measurement results,comprehensive evaluation of geological,hydrological conditions and soft foundation conditions of the project area was carried out,obtained basic soil indicators of cofferdam filling and stratum.At the same time,the method selected for slope stability analysis was carried out.The sliding inclinometer was used to monitor the deep displacement of the cofferdam slope.According to the analysis of the displacement characteristic curve of the actual survey,it is known that the cofferdam slope of the engineering backfilling area is in an unstable state,and the possible sliding surface is located in the deeper part.And the displacement at the foot of the slope is obvious.Combined with the actual observation and analysis at the site,it was decided to use the anti-slide pile or back pressure method for reinforcement.In order to further determine the stability of the cofferdam slope,the technical principles of the solution steps,fluid-solid coupling and strength reduction method of FLAC3D software were studied.The FLAC3D analysis model was established and the stability of the slope was calculated by the strength reduction method.Comparing the calculation results obtained by the traditional analysis method,it is verified that the FLAC3D software is used to analyze the actual engineering slope by the strength reduction method.The stability of the slope under different water levels was simulated and analyzed,and the effect of high water level on the stability of the cofferdam slope was the largest.Therefore,the subsequent numerical simulations used it as the most unfavorable water level analysis.By comparing the numerical simulation results of the anti-slide pile reinforcement scheme and the back pressure reinforcement scheme,both reinforcement schemes could stabilize the cofferdam slope.Finally,comparing the simulation design results of the optimized design and the cost of the two schemes,it is more appropriate to use the back pressure method to strengthen the cofferdam slope.Based on this,the process flow,technical points and precautions of the back pressure method construction are summarized for reference for subsequent construction.