Abstract: In order to investigate deeply the developmental mechanism and scientific prevention-cure method of the disease in the runoff-type gully on rammed earth ruins, the investigation of the factors of influence upon the activity of the runoff-type gully development is carried out. Therefore, by means of selecting the Great Wall of Mingdynasty with linear by rammed earth ruins, which has identical zone of preservation, era-technique attribution, and distribution of investigation, as investigation object and conducting the survey and statistics of the quantity and modal feature of the gully on the ruins with length of 1 km at 17 sites of Ming dynasty Great Wall, the linear density and shrinkage rate of the gully as its eigenvalues for characterization of activity of gully development at an area are presented. Then, the disintegration rate, liquidity index, cohesive force, annual average rainfall, annual average daily extreme rainfall, and annual average temperature diurnal variation as main influence factors are screened with regression analysis method. Finally, the evaluation model established by means of entropy weight and gray correlation method and it is found that the magnitude sequence of influence factors will be disintegration rate > liquidity index > cohesion force > annual average temperature diurnal variation > annual average rainfall > annual average daily extreme rainfall. The influence of internal factorof rammed earth is more significant than that of environmental factors in the process of runoff-type gully development of rammed earth ruins in arid areas of northwest China.

Key words: rammed earth ruins, runoff-type gully, developmental eigenvalue, entropy weight method, grey correlation