Different Effects Of Sunny And Shady Slop In Undercutting Area Study The Great Wall In Ming Dynasty Relics Of The Hxi Corrido

The formation and development of undercutting area is one of the typical diseases controlled by environmental factors and will commonly and directly do harm to earthern ruins in arid region,which influence global stability and instability mode of earthenruins.greatly, so it is an important research content for the scientific research and effective protection of the earthen ruins.Therefore, through investigation of morphology and amount of erosion of results of salt content in the erosion area,real-time monitoring result of temperature and moisture content of southern and northern slop during centralized rainfall process,analysis of wind speed,direction for decades and the environmental characteristics of the Great Wall on Ming Dynasty ruins in 12 cities along the Hexi Corridor in typical area of erosion area, it is found that there existes significant differences in the occurrence conditions and the effects of the soil salinity deterioration and aeolian ullage loss in the undercutting area of the southern and northern slop, therefore difference effect of undercutting area in southern and northern slop of the Great Wall on Ming Dynasty ruins are put forward. Combined analysis of soil particle size distribution characteristics after experiment in laboratory on remodeling samples mixed with different contents of NaCl and Na2SO4 and undergoing 3,6, 9, 12 dry-moisture cycles after desalination, with sonic wave testing and wind tunnel simulation experiment, it proves that there exists effects of different effects of the undercutting area in the southern and northern slop.Finally, combined survey analysis with experimental results,the formation mechanism and forming process of the experimental results are preliminary discussed., in order to provide theoretical support for the protection and reinforcement of the Great Wall in the northwest region in the whole.The research results show that:(1)According to the space form,the form of undercutting area in southern and northern slop of the Great Wall on Ming Dynasty ruins is devided into three kinds, namely, the shape of the bow, the rectangular and the semi- arch, which provides reference basis of quantitative calculation of the development degree of the erosion damage.(2)Through the investigation, monitoring and analysis of the morphology, salt, dry and wet conditions, and the characteristics of the wind field of the southern and northern slop of the the Great Wall on Ming Dynasty ruins,it is found that influence factors behavior differently in the same spatial and temporal scales, which provides preconditions for the formation of undercutting area in southern and northern slop,and they are essential factors.(3)During the simulation experiments of saline and wind erosion, samples of different salt type and salt content experienced different runs of dry-wet circles influence saline deterioration and wind erosion loss differently,the higher salt content, the more cycles, the more significant the effect of deterioration and loss of wind erosion of the sample structure, and the effect of samples Na2SO4 are stronger than NaCl samples, which shows that the increasing number of cycles accelerate the deterioration of soil structure. And the higher salt content,the more obvious result, which makes soil particles more easily wind erosed.(4)Through the research results of undercutting area of southern and northern slop,investigation and analysis of quantitative experimental study,it proves that there exists different effects in undercutting area of the southern and northern slop. It also reveals that the northern erosion area in shape and volume are greater than that inthe southern erosion area, because the content of soluble salt, wet and dry conditions and wind field characteristics and other factors affect saline deterioration and the wind erosion loss effect more remakly.(5)Wave velocity, wind velocity and soil particle fractal dimension of each remolded soil were analyzed by linear correlation,,it reveals that there exists a good correlation between these three.(6)Furthermore, combined the changes in salinity, temperature and water content of undercutting area in southern and northern slop with theoretical analysis, it is reveals the mechanism of deterioration and the mechanism of deformation and failure.