Based on AHP-fuzzy comprehensive evaluation method of cement mixing pile quality evaluation and application

Abstract

Cement mixing piles are widely used in many soft soil areas in China to treat weak foundations. However, in view of its hidden engineering characteristics, how to evaluate its post-construction quality in a timely and effective manner is still a lack of scientific and effective method. Taking a soft foundation mixing pile treatment project in Zhongshan City, Guangdong Province as an example, it is based on the intelligent monitoring system combined with the field tests. It uses the AHP-fuzzy comprehensive evaluation method to evaluate the quality of cement mixing piles. Firstly, the evaluation index and membership function of the quality of the mixing pile are determined, and then the weight of the corresponding evaluation index is calculated by the analytic hierarchy process. Secondly, the fuzzy comprehensive evaluation method is used to evaluate the quality of the cement mixing pile. Finally, the evaluation result are compared with the engineering practice. The result show that the error between the monitored pile length and the actual pile length is less than 2%. The goodness of fit between the ash content of the monitoring section and the strength of the pile body is high, and the goodness of fit between the average speed of the drill pipe and the integrity of the pile body is also high. The fuzzy comprehensive evaluation result of pile quality are in good agreement with the core sample characteristics of the core sample. The result show that the application of this evaluation index system combined with the fuzzy comprehensive evaluation method can well reflect the result of the quality inspection of cement mixing piles in practical engineering, and verify the feasibility of this method for the rapid evaluation of the quality of cement mixing piles. It provides a reference for improving the content of the construction stage of cement mixing piles and improving the construction quality.

Keywords

soft soil area / cement mixing pile / construction quality assessment / analytic hierarchy process / fuzzy comprehensive evaluation method