Evaluation Method Of Foundation Coefficient Of Two-parameter Foundation Based On Dynamic Characteristic Test

With the large-scale and heavy construction of modern construction projects,researchers urgently need to update the theory and technology of foundation,and the foundation model and foundation coefficient were the breakthrough points of foundation engineering research.For more than one hundred years,people studied the foundation model based on Winkler One-parameter foundation model.Winkler foundation model simulated the relationship between soil load and settlement simply and intuitively,but the biggest drawback of Winkler foundation model was that the foundation soil medium was not continuous.Later Filonenko-Borodich Helenyi et al proposed a new foundation model-Two-parameter foundation model,the foundation coefficient need Two-parameter representation:compression foundation coefficient k and shear foundation coefficient G.This model more accurately reflected the real situation of the foundation,and inherited the simple characteristics of the theoretical form of the Winkler foundation model.But at this stage,the research on Two-parameter foundation was not comprehensive,in this paper the foundation coefficient of Two-parameter foundation model was obtained to do the deep research and analysis,in order to promote the wide application of Two-parameter foundation in foundation engineering.This paper reviewed research progress at home and abroad,the application specification process of foundation coefficient of the technical standards in our country after 70s of last century,the research results of Two-parameter foundation,and the dynamic response research of Two-parameter foundation power.The method of acquiring the One-parameter foundation coefficient was briefly introduced,and based on the results and references of recent researchers,the two new methods for obtaining the Two-parameter foundation coefficient was presented:One method was that based on the genetic algorithm and the generalized thickness element program of Two-parameter foundation,the back analysis of the result of foundation slab was done to identify the foundation coefficient(compression foundation coefficient k,shear foundation coefficient G);The other method was that based on the Two-parameter foundation-energy equation of the rigid plate system,and then the foundation coefficient was obtained combining with the static load test of the field rigid plate.This laid a study foundation for obtaining the Two-parameter foundation coefficient of dynamic characteristics test of the field rigid plate power.Under the premise of the Two-parameter foundation model,the independent foundation(replaced by concentrated load rigid plate)under the column was taken as the object of study.The two-parameter foundation was established by using energy method and Hamilton principle-basic dynamic equation.So,a new measuring method of foundation coefficient was obtained:to obtain the dynamic foundation parameter(k,G)by using the rigid plate dynamic test and establish the energy equation.Based on the dynamic measurement characteristics of pulse method,using the Dongfang INV data acquisition instrument,DASP-V10 spectrum software and other testing equipment,the dynamic test of the rigid plate group of two different test sites was carried out and the natural frequency f of the rigid plate was obtained.The natural frequency(angular frequency)? of the rigid plate was brought into the deduced Two-parameter energy equation,and the foundation coefficient reaction(G)was obtained to verify the reliability of the energy equation.Finally,the Winkler and the Two-parameter ground model were established by using the SAP2000 analysis software,and the relevant parameters were brought into the established model,and the finite element analysis was carried out.The results of finite element analysis were compared with the results of field rigid plate test,and it was found that the two results were in good agreement.And then the accuracy of the energy relation of the foundation coefficient of the Two-parameter subgrade was verified.So the Two-parameter foundation coefficient obtained in practical engineering could be used.