洪渡河堤防工程粉质砂土循环加卸动荷载下动力特性研究

Study on the Dynamic Characteristics of Silty Sand Soil under Cyclic Loading and Unloading Conditions in the Hongdu River Embankment Project

为研究洪渡河遵义段堤防工程粉质砂土的动力特性,文章通过现场钻孔取样,采用循环加卸动载的试验方法,开展了粉质砂土动力特性试验分析。研究表明,固化剂掺量不会从根本上改变土样内部颗粒结构及土样孔压变化历程,而围压作用会改变土样孔压演变历程,围压对土样孔压影响效应高于掺量因素。固化剂掺量以及围压作用,均不会改变动弹性模量的演变趋势,但会影响动弹性模量进入稳定段的应变节点;掺量愈多,动弹性模量值愈小,而围压的影响与之相反。掺量愈大,则进入阻尼比稳定节点愈早,且掺量以及围压作用,均不会改变阻尼比宏观变化特征;掺量、围压对阻尼比的影响分别为正相关、负相关。上述结论可为堤防工程粉质砂土的动力特性认知以及动荷载试验设计提供参考。

In order to study the dynamic characteristics of silty sand soil in the embankment project of Zunyi section of Hongdu River,this paper conducts an analysis of dynamic characteristics of silty sand soil using field drilling sampling and cyclic loading and unloading test methods.The study shows that the amount of stabilizer mixed in does not fundamentally change the internal particle structure of the soil sample or the history of pore pressure changes within the soil sample.However,the action of confining pressure alters the evolution of soil sample pore pressure,with the effect of confining pressure on pore pressure being more significant than the factor of mixture amount.The addition of a stabilizer and the action of confining pressure do not change the evolution trend of the dynamic elastic modulus of the samples,but they do affect the strain node at which the dynamic elastic modulus becomes stable.The more the amount of stabilizer added,the smaller the value of the dynamic elastic modulus,while the effect of confining pressure is the opposite.The greater the amount of the mixture,the earlier the damping ratio reaches a stable node.The mixture amount and confining pressure do not change the macroscopic characteristics of the damping ratio variation;the effects of the mixture amount and confining pressure on the damping ratio are positively and negatively correlated,respectively.The above conclusions can provide a reference for understanding the dynamic characteristics of silty sand soil in embankment projects and for the design of dynamic load tests.