Study On The Correlation Between Fractal And Engineering Of Rammed Earth Of The Ming Great Wall On The Foot Of Qilian Mountains

Rammed earth,a building material used around the globe for its decorative and easy-to-be-worked features from past to present,is widely used as foundational materials in Great wall of Ming Dynasty,which is world cultural heritage and a perfect production finished by ancient people.Recent years,the research on Great wall of Ming Dynasty attracts a lot of scholar’s attention for the rise of subject of civil engineering,geological engineering and historic preservation.As a result of this thought,18 samples were selected at the south and north foot of Qilian mountain to rounded analyze the engineering geological characteristics of Ming Dynasty.Field investigation and laboratory test were applied to analyze the characteristics about resistance to wind and rain erosion and mechanics to find the universal and straight at the 18 samples.In this study,the property of rammed earth were investigated at micro perspective both grain composition and distribution and pore fractal.The results are followings:(1)There are lager differences in compression and shear resistance of rammed earth of 18 Ming Great Wall sites located at two feet of Qilian Mountain between north and south.According to such change rules,that rammed earth can be divided as stronger and weaker compressive resistance types.Similarly,it can be divided as stronger and weaker shear resistance types;(2)the property of resistance to wind and rain erosion of rammed earth of 18 Ming Great Wall sites located at two feet of Qilian Mountain between north and south is different.So,according to the property,we dvided the samples into four pieces,namely strong and weak ability to resist wind erosion,and strong and weak ability to resist rain erosion.(3)in addition,the samples are regarded as owing better engineering characteristics and ordinary engineering feature,based on their anti-compression property,resisting shear property and the ability to resist wind and rain erosion.(4)Based on fractal theory and nonlinear fitting,the rammed earth located at such sites has greater granularity and pore fractal properties.According to fractal result,it is divided as large and small fractal dimension values,and there is one to one relationship between fractal dimension values and their interval sections.(5)Indexes characterized by mechanical properties,wind and rain resistance to erosion of such two types of rammed earth have certain function relation with fractal dimension values of granularity and porosity.By association study between each index and fractal dimension value discussed above,the superiority-inferiority of such rammed earth from 18 sites can be assessed,and finally,the fractal dimension value can be accessible index to determine the superiority-inferiority of engineering properties of rammed earth.