Prediction Of Long-term Settlement Of Soft Ground Of Chengdu Tianfu International Airport

The airport attaches great importance to the stability of the airport's foundation during the construction process.Excessive settlement of the foundation after construction and excessive uneven settlement will cause the airport runway to crack and the unevenness of the road surface.Based on the engineering of Chengdu New Airport,this paper conducts a systematic research on the foundation settlement mechanism,settlement law,and settlement influencing factors based on engineering monitoring data and laboratory test results.Sub-consolidation settlement model,curve fitting method and numerical calculation method are used to predict the post-construction settlement of the airport.The topographic and geological conditions of Chengdu Tianfu International Airport are complicated,and the soft soil on the site is widely distributed and uneven.Since the settlement of the airport after construction is mainly caused by the sub-consolidation of soft soil,the following research is conducted on the soft soil of the airport.1.Made a detailed summary of the topography of the airport,and systematically summarized the groundwater level,the distribution of soft soil,the causes of soft soil,and the impact of soft soil on ground settlement.The site's soft soil characteristics,ground treatment methods and monitoring conditions are explained in detail.It is found that the magnitude of the overburden load and the speed of the applied load have a greater impact on the settlement of the soft soil foundation.2.Perform indoor uniaxial compression test on the soft soil of the airport foundation,and use the Cassagrande method to obtain the preliminary consolidation pressure of the soft soil of about 100 Kpa,The over-consolidation strength OCR of soft soil is 1.13,and the soil is over-consolidated.According to the curve,the primary and secondary consolidation time points are around 100min3.Analyze and explain the calculation model of secondary consolidation settlement,and use the more mature Buisuman model to calculate the secondary consolidation settlement of the site monitoring points.Secondly,the curve fitting method is used to fit the curve of the airport subsidence by the hyperbola method,Asaoka method and Hoshino method,and then predict the 30-year post-constructionsettlement.The comparison results show that the error of the hyperbola method is small and the predicted value is more reliable.4.Calculate the foundation section of the airport with the plaxis numerical calculation software.The model simulates various ground treatment methods.The changes of the added underground space with time and the construction sequence are close to the actual construction,It was found that the calculated value and the calculated value of the sub-consolidation settlement model were generally larger than the predicted values of curve fitting...