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西北干旱地区土遗址受风化、风蚀等破坏严重,大量土质文物亟待加固抢修。加固后土遗址的各耐环境因素及加固机制研究是土遗址加固的理论基础。首次引入颗粒元程序PFC,通过改变模型中颗粒间平行连接强度,对硅酸钾(简称PS)加固前后的土样进行数值模拟。在考虑实际土样颗粒粒径和密度的前提下,拟合了生土PS加固前后的抗压和抗拉强度,并将拟合后的颗粒元模型应用于风蚀模拟。通过随机生成挟沙风颗粒,以一定的速度撞向土体,模拟挟沙风的吹蚀作用。挟沙风颗粒数与循环步数成正比例,因此,可以用挟沙风颗粒数来代表吹蚀时间的长短。挟沙风颗粒的速度则代表挟沙风风速。模拟结果表明,在20 m/s的挟沙风吹蚀作用下,风蚀程度随吹蚀时间的增加而增大,未加固土样的风蚀程度增幅度远大于加固土样;同样吹蚀时间条件下,加固土样的抗风蚀强度明显高于未加固土样。这些模拟结论与风洞试验结果的统计规律一致。本研究拟合的颗粒流模型可进一步应用于PS加固机制研究及耐风蚀、雨蚀、冻融等诸环境影响分析研究。
The soil sites in the arid area of Northwest China are seriously damaged by weathering and wind erosion, and a large number of soil relics need to be reinforced and repaired. The study of various environmental factors and reinforcement mechanisms of the relics after rehabilitating is the theoretical basis of the remediation of the relics. The particle program PFC was introduced for the first time. The soil samples before and after the reinforcement of potassium silicate (PS) were numerically simulated by changing the parallel connection strength between particles in the model. Under the premise of considering the particle size and density of the soil samples, the compressive strength and tensile strength of the PS before and after reinforcement were fitted, and the fitted particle model was applied to the wind erosion simulation. Through random generation of sand particles, crashed into the soil at a certain speed, simulating the blowing effect of sand with wind. The number of sand particles with sand circulation is proportional to the number of steps, therefore, sand particles can be used to represent the number of blown away the length of time. The speed of sand particles with sand wind speed on behalf of sand. The simulation results show that the degree of wind erosion increases with the blowing time under the action of wind-blown wind with a velocity of 20 m / s, and the degree of wind erosion increases more significantly than that of the unaffected soil; , The wind erosion resistance of the reinforced soil samples is obviously higher than that of the un-consolidated soil samples. These simulation results are consistent with the statistical rules of wind tunnel test results. The particle flow model fitting in this study can be further applied to the study of PS reinforcement mechanism and environmental impact analysis such as wind erosion, rain erosion, freezing and thawing.