腐蚀环境下纳米SiO_(2)改良水泥土动弹性模量与阻尼比试验  

Experimental Study on Dynamic Elastic Modulus and Damping Ratio of Soil-cement Modified by Nano-SiO_(2)in Corrosive Environment

作　　者：庄心善 杨本驰 寇强 ZHUANG Xinshan;YANG Benchi;KOU Qiang(School of Civil Engineering,Architecture and Environment,Hubei University of Technology,Wuhan 430068,China)

机构地区：[1]湖北工业大学土木建筑与环境学院,湖北武汉430068

出　　处：《工程科学与技术》2025年第1期253-263,共11页Advanced Engineering Sciences

基　　金：国家自然科学基金项目(51708190)。

摘　　要：近海地区工程建设项目大多受海水腐蚀和动荷载影响,为改善近海地区水泥土基础的力学性能,选取广州某沿海工程黏土制备纳米SiO_(2)改良水泥土试样,利用GDS真(动)三轴仪对改良水泥土进行循环加载试验,探究腐蚀状态下纳米SiO_(2)对水泥土力学性能的影响,分析不同腐蚀天数、不同海盐腐蚀浓度下改良水泥土的动弹性模量及阻尼特性。结果表明:纳米SiO_(2)改良水泥土动弹性模量随海盐腐蚀溶液浓度增大逐渐减小,其增长速率随海盐腐蚀时间增长逐渐减弱;与普通水泥土相比,在水泥土中掺入纳米SiO_(2)可明显增大水泥土动弹性模量,提高土体抗腐蚀能力;利用Konder模型得出水泥土动弹性模量倒数与动应变呈良好的线性关系,且纳米SiO_(2)改良水泥土最大动弹性模量E_(d0)相比于普通水泥土有明显提高;采用Darendeli模型对水泥土动弹性模进行分析,得到纳米SiO_(2)改良前后水泥土动模量比衰减模型,该模型能较好地描述海盐腐蚀环境下水泥土动弹性模量随动应变的变化规律;在海盐腐蚀时间相同的条件下,纳米SiO_(2)改良水泥土滞回圈面积S、阻尼比λ随海盐腐蚀溶液浓度增加不断增大,且均小于普通水泥土,水泥土经纳米SiO_(2)改良后,阻尼比λ的增长速率及增长量明显减小。在沿海腐蚀环境下,纳米SiO_(2)可有效提高水泥土力学性能,探究如何改良水泥土动力特性可为实际工程建设提供有效参考。Objective Most construction projects in offshore areas are affected by seawater corrosion and dynamic loads.Many of these projects have caused a series of accidents due to the corrosion of cement soil,such as the swelling and collapse of road bases and the cracking and destruction of foundations.From the perspective of dynamic load,cement soil is subjected to various stresses,including earthquakes,typhoons,vehicle-induced crushing,wave impacts,and other loads during construction and use,which inevitably aggravate the deterioration of the cement soil foundation.Methods In order to improve the mechanical properties of cement soil foundations in offshore areas,a coastal engineering clay from Guangzhou is selected to prepare nano–SiO_(2)-improved cement soil specimens.The GDS true(dynamic)triaxial instrument is employed to conduct cyclic loading tests on the improved cement soil.The specimens are saturated in a vacuum using a saturator,placed in a seawater solution for corrosion after saturation,and then subjected to counterpressure saturation using the GDS true(dynamic)triaxial instrument.The peripheral pressure is set at 200 kPa,with a loading frequency of 1 Hz(sine wave),an initial axial force of 2200 N,and a dynamic stress amplitude(σ_(d))of 100,200,300,400,500,600,700,800,900,and 1000 kPa.The specimens are loaded in ten stages and vibrated 10 times in each stage to investigate the effect of nano–SiO_(2)on the mechanical properties of cement soil under corrosion conditions.To study the dynamic elastic modulus and damping characteristics of the improved cement soil under varying corrosion durations and concentrations,the changes in the dynamic elastic modulus of cement soil before and after improvement are compared.A dynamic elastic modulus ratio decay model is established,and the influence of changes in the damping ratio is analyzed.Results and Discussions The results showed that under the combined effects of cyclic loading and seawater corrosion,the dynamic elastic modulus of cement soil before and after na

关 键 词：海盐腐蚀溶液 水泥土 纳米SiO_(2) 动三轴试验 动弹性模量 阻尼比 

分 类 号：TU411[建筑科学—岩土工程]