Study On The Mechanical Test Of Herb Root System On Kaifeng Ancient City Wall

Kaifeng city wall is one of the most complete existing ancient city walls in China.The wall is a state-level cultural relic protection site with important humanistic,historical and tourist values.However,with time going on,the engineering safety and stability of the city wall are in urgent need of systematic research and analysis.After investigating the current disease status of the Kaifeng ancient city wall,we find that the city wall has partial collapse,cracking,weathering,salting out,crisp powder,spalling,recession,nonuniform settlement and other diseases.And there are a variety of plant communities on the slope of city wall.As far as the slope,the plant root system can play a better role in soil and slope protection.As for the wall space,the growth of the plant root system will accelerate the development of disease,which affects the monolithic stability of the city wall.At present,most of the research on the city wall and plant roots focuses on the restoration,development and cultural value of the ancient city wall.While,the research on plant roots mostly concentrates on the stress model,theoretical strength,composite materials,etc.However,there are few studies on the influence of plant roots on the city wall.Thus,further research is needed.This paper focuses on Kaifeng city wall,by using the method of composite theoretical analysis and soil test.The major contents studied are as follows:(1)The basic physical parameters of the slope soil of the city wall are obtained through the particle screening test,consolidation test,and boundary moisture content test.The mechanical performance parameter of slope soil were obtained through freezing and thawing cycle test and direct shear test.(2)To collect typical plant samples of the city wall and plant the seasonal plants,and to prepare the root-soil composite test piece,then the plant root system is cleaned.Through mechanical test,the effect of plant root system on the slope soil of the city wall was analyzed.(3)According to theoretical analysis,the main component of wall space soil should be calcium carbonate.A small amount of wall space soil was taken for XRD characterization test to compare the peak pattern and verify the correctness of the analysis results.(4)The city wall space soil was prepared manually,and the performance parameters of the quicklime powder were measured.The quicklime powder and the silty clay on the slope of the city wall were evenly mixed by volume ratio,and the glutinous rice slurry was added for mixture.make the lime-siol of root-soil complex test piece,through mechanical tests,data analysis,the effect of plant root system on the artificial preparation of city wall space soil was studied.