Research For Deep Foundation Pit Supporting And Construction Risk Assessment

With the continuous development of China’s economy and urban construction, the city’s land resources become tighter, the development and utilization of urban underground space has become a trend, foundation excavation depth and increasing scale. Because deep excavation has large investment, risk factors and more significant impact on the social environment characteristics, when major excavation accidents have occurred, causing huge loss of property to the state and the adverse social impact. Excavation is a high-risk construction, excavation construction process to establish a risk management system, the construction excavation risk assessment, followed by implementation of the construction risk control is particularly necessary.(1) This paper summarizes the current research to assess the deep pit of support and construction risk, introduces the basic theory of deep foundation engineering calculations. Chongqing Rural Commercial Bank deep excavation based, according to the excavation site engineering geological conditions and characteristics of the surrounding environment, the excavation to determine the form of pile-anchor support, the stability of deep excavation were calculated, and developed a pit monitoring programs.(2) Describes the existing deep foundation construction risk assessment methods, pointing out the various methods in use in the existing problems. In summary accident type deep excavation, foundation pit based on the force and deformation parameters of statistical indicators on the proposed multi-parameter safety assessment methods. Relying on deep excavation monitoring data, establish a quantitative relationship between the various mechanical indicators for monitoring data, the main criterion is the maximum surface subsidence ① maximum surface subsidence δvm <maximum displacement δhm ② envelope surface subsidence trough between body volume Vs soil volume loss of 0.5 to 1.5 Vw③calculate the safety factor K between 0.5 and 2, in order to assess the risk of construction pit. This method can evaluate a single parameter warning methods can not determine the security risks of the project, a single parameter of existing risk assessment methods are a good supplement.(3) Based on monitoring data pit in multi-parameter risk assessment on the basis of deep foundation, excavation using inverse analysis method to predict the dynamic risk assessment. Through the establishment of a three-dimensional solid model of excavation, the risk assessment in a multi-parameter library, post-excavation of dynamic risk assessment of the potential sources of risk excavation judge warning.