轻质土动力特性研究进展

Research progress on the dynamic characteristics of lightweight soil

轻质土具有轻质、高强、保温、隔振、环保、经济等优点,在路基回填、软基处理、隧道减荷等岩土工程领域具有广阔的应用前景.作为新型土工材料,交通荷载、地震荷载、波浪荷载等振动荷载对轻质土力学特性的影响引发众多关注.本文阐述了配合比(轻质材料含量、固化剂掺量、含水率等)、应力状态、振动频率、干湿交替和冻融循环等因素对轻质土动力特性的影响规律,总结了轻质土动剪切模量和阻尼比计算模型.研究发现水泥等固化剂的使用大幅提升了轻质土抵抗动荷载的能力,轻质土独特的孔隙结构可显著提高其隔振效果,干湿、冻融循环会导致轻质土动力学性能劣化,在实际工程中可通过设置防水层延长其服役寿命.通过模型试验和数值模拟验证了轻质土在实际工程中具有良好的动力稳定性和耐久性.目前轻质土动力特性研究尚处于起步阶段,新型固废轻质土动力学性能尚未深入研究,复杂环境因素与动荷载耦合作用下轻质土的作用机理、力学性能和本构模型研究,以及轻质土在不同工程背景下的设计施工方法研究仍需探索.

Lightweight soil is a novel technological material that boasts characteristics such as low density,high strength,thermal insulation,vibration isolation,environmental friendliness,and cost-effectiveness.These features make it highly suitable for a wide range of applications in geotechnical engineering,including roadbed backfill,soft foundation treatment,and tunnel load reduction.The influence of vibration loads resulting from transportation,earthquakes,waves,and other factors on the mechanical properties of lightweight soil has garnered considerable attention in recent research.This paper expounds on the influence of factors on the dynamic deformation characteristics and dynamic strength properties of lightweight soil.These factors include the mix ratio(such as the content of lightweight materials,dosage of curing agent,and moisture content),stress state,vibration frequency,dry–wet alternation effect,and freeze–thaw cycle.Additionally,we summarise the calculation model for the dynamic shear modulus and damping ratio of lightweight soil.The findings reveal that the incorporation of curing agents,such as cement and fly ash,substantially improves the resistance of lightweight soil to dynamic loads.Additionally,the distinctive pore structure of lightweight soil markedly enhances its vibration isolation effect.As dynamic strain increases,there is a nonlinear decrease in the dynamic modulus of lightweight soil while the damping ratio increases nonlinearly.Adjusting the content of lightweight materials and the dosage of curing agents can markedly improve the seismic reduction effect of lightweight soil,thus granting it greater dynamic stability.The coupling effects of dry–wet cycles,freeze–thaw cycles,and dynamic loads may lead to a degradation in the dynamic performance of lightweight soil.To extend its service life in practical engineering applications,the implementation of a waterproof layer is recommended.Model tests and numerical simulations substantiated the commendable dynamic stability and durability of lightweight soil in real-world engineering scenarios.Finally,following a comprehensive literature review,this paper identifies potential research directions.The study of dynamic characteristics in lightweight soil is still in its infancy,with the dynamic properties of novel solid waste lightweight soil remaining largely unexplored.Further exploration is required to fully understand the response mechanisms,mechanical properties,and constitutive models of lightweight soil under the combined effects of complex environmental factors and dynamic loads.Additionally,there is a need for continued research into the design and construction methods of lightweight soil across various engineering settings.In conclusion,this paper serves as a valuable reference for investigating the dynamics of lightweight soil and its extensive application in geotechnical engineering.