西北地区典型遗址土动模量与阻尼比特性试验研究

通过室内动三轴试验,研究了西北地区遗址土体的动本构关系,得到了模型参数,分析了遗址土体的动剪模量比和阻尼比的特性,并通过归一化处理得出模型参数,结果表明:遗址土体符合Hardin-Dinevich双曲线模型,其相关系数均大于0.991 7,模型参数a、b与土样密度不存在相关性;在相同荷载下,密度越大,动应变和动残余应变越小,其中陕西定边陡沟子明长城墙体土承受动荷载能力下降较快,而草滩段秦长城墙体、瞭望台台基处初始弹性模量和初始剪切模量较小,三处土体硬度较小,易于遭受病害侵蚀破坏,需进行重点加固维护;遗址墙体所建窑洞处土体强度和硬度明显大于长城墙体,动弹性模量和动剪切模量约为其墙体2倍。草滩段瞭望台土体强度和硬度明显大于同地区长城墙体;遗址土体的动剪切模量G/G0随着动剪应变γd的增加而减小,且密度越大,衰减速度越快,阻尼比D随着动剪应变γd的增长,呈现先缓慢增加-急剧增加-缓慢增加的过程,且密度越大,阻尼比越大。按建造年代、建造形制和用途划分、所处地区对典型遗址进行动力特性的对比分析,为今后土遗址加固保护提供理论基础和参考依据。

Experimental study on soil dynamic modulus and damping ratio characteristics of typical sites in Northwest China

Through the indoor dynamic triaxial test,the dynamic constitutive relation of the soil in the northwest china is studied.The model parameters are obtained.The dynamic shear modulus ratio and damping ratio of the soil are analyzed and normalized.The model parameters are obtained.The results show that the ruins soil of the site conforms to the Hardin-Dinevich hyperbolic model,and the correlation coefficient is greater than 0.991 7.There is no correlation between the model parameters a and b and the soil density. Under the same load,the density is higher,the smaller the dynamic strain and the dynamic residual strain, and the faster the soil body loss resistance to the dynamic load at the Dougouzi of the ming great wall.the initial elastic modulus and initial shear of the wall and lookout platform is small at the Caotan of the Qin Great Wall.The hardness of three soils is small, it is easy to suffer from disease erosion and damage,and it needs to be strengthened and maintained. The strength and hardness of the cave dwellings built by the site walls are obviously larger than that of the Great Wall, and the dynamic elastic modulus and dynamic shear modulus toits wall is 2 times. The strength and hardness of the lookoutplatform of the Caotan section is significantly larger than that of the Great Wall wall in the same area;the dynamic shear modulus G/G0 of the ruins soil decreases with the increase of the dynamic shear strain γd, and the density is higher, the decay rate is faster,the damping ratio D increases with the increase of the dynamic shear strain γd, and the process of slowly increasing-sharply increasing-slowly increasing, and the density is greater,the damping ratio is greater.According to the construction age, construction shape and area, the comparative analysis of the dynamic characteristics of typical sites,providing the theoretical basis and reference basis for the reinforcement and protection of earthen ruins in the future.