Application Research Of Steel Pipe Pile Support System In Cast-in-place Box Girder Of Soft Foundation Section

The steel pipe pile support system involved in this paper is mainly used for temporary support of cast-in-place concrete beams with high support formwork.This support form is adopted in the soft foundation section,including two parts: the foundation of the support system and the support system(steel pipe pile support system for short).Traditional high support template cast-in-place concrete beam temporary support system,Generally,the full hall supporting construction system is adopted and this supporting system is not only the construction period long,technical economy poor but also set in the soft ground road uneven settlement problems easily which cause in the process of cast-in-place concrete beam cracks and poor prestressed quality hidden trouble,so as to affect the quality of the cast-in-place concrete beam.The steel pipe pile supporting system can avoid and reduce the deficiency of traditional full hall supporting construction and greatly improve the technical economy.Since the 1970 s,many scholars and engineers at home and abroad have carried out a lot of theoretical research and engineering practice on the steel tubular pile support system,and obtained some useful results and conclusions.However,due to the complexity of the problem,coupled with a strong regional and specific engineering characteristics,so that further research in this area is still necessary.This paper based on Guangdong Xintai highway south extension line engineering T contract section cast-in-place concrete beam,from the different processing forms the basis of settlement,uneven settlement of ages of the cast-in-place concrete effect,bearing capacity and stability of bracing system itself,as well as the construction process quality control.The characteristics and application of steel pipe pile support system in soft soil foundation are studied.The main work is as follows:(1)According to geological conditions and construction purposes,this paper studies the characteristics and variation rules of settlement generated by different foundation treatment forms,provides concrete treatment schemes for the section of cast-in-place concrete beam operation in contract T section of the south extension line of the Xintai highway,and analyzes the settlement of cast-in-place concrete beam during operation.(2)By analyzing the stress change law of cast-in-place structures at different initial ages under differential settlement load,the minimum differential settlement value of plastic deformation in each stage is given;The deformation law of cast-in-place structure is calculated by using the beam model of elastic foundation and the optimization analysis method to ensure the quality of cast-in-place structure on soft foundation section is given.(3)According to the specific conditions of the contract section T of the southern extension line of Guangdong Xintai highway,the construction technology and operation plan of the cast-in-place concrete beam with high support formwork are given.The engineering characteristics of the steel pipe pile support system,such as the bearing capacity and stability,are calculated,and specific quality requirements are put forward.(4)Based on Guangdong Xintai highway line extension engineering K00 + 000 ~ K00 + 000 T contract make the corresponding monitoring plan.Analyzed and calculated the differential settlement caused by the practical working condition in the process of cast-in-place concrete beam.The numerical results are compared with the measured data.In order to demonstrate the correctness of the research method.And ensure the feasibility of the maximum differential settlement allowable value of cast-in-place concrete beam quality.