Dynamic Optimum Design Of Deep Foundation Support Based On Non-parametric Regression

At present,the foundation pit engineering in our country is limited by the size of the construction site,the scale of the foundation pit is developing towards the trend of getting deeper and deeper.With the increase of the number and scale of deep foundation pit engineering,people have the paid more attention to the safety and economy of the retaining structure of deep foundation pit.The existing construction methods of deep foundation pit are as follows:smooth practice and inverse method.It should be noted that whatever construction methods is chosen in practice,in the design and construction phase many uncertain factors we should face with,such as geological conditions,groundwater conditions,the impact of weather changes,the surrounding environment,construction personnel management,etc.And the first problem is the complexity of soil parameter selection.Therefore,based on the engineering survey of the soil parameters to design the foundation pit support structure(static design),may be too conservative not economy.Secondly,in the process of construction of deep foundation pit,the soil parameters have been changed due to the disturbance of soil mass,the surrounding environment of the construction site will also be changed,the original design by the soil parameter data obtained from the survey may not be safe and reliable because of these changes.In order to solve the current shortcomings of the static design scheme of foundation pit,we can use the concept of dynamic design to finish the construction design of deep foundation pit.The dynamic design concept is that in the process of construction,the soil parameters are analyzed according to the information of real-time monitoring feedback,on the basis of the back analysis of the equivalent soil parameters,the construction method and the design of the original support are adjusted,which makes the design of the construction to achieve the goal of safety and economy.The selection of the back analysis method of soil parameters in the dynamic design process is very important,so this paper proposes a back analysis method by non-parametric regression,this method can provide a new idea for the dynamic design of deep foundation pit support.The dynamic design idea of this paper is creating a response surface by the uniform test and non parametric regression technique,on the basis of the response surface,according to the feedback information of real-time monitoring,combined with Monte Carlo simulation technology,to back analysis the soil parameters,then using the equivalent parameters of back analysis to dynamic adjust the original design of the support structure.This method is applied to the pile anchor support and retaining ring support two kinds of practical engineering cases,the dynamic design optimization of the support structure and the original design method are compared and analyzed to prove that the method has good applicability in the dynamic design of deep foundation pit support.