玄武岩纤维提升水泥土抗压性能试验研究  

Experimental Study on Improving the Compressive Performance of Cement-Soil with Basalt Fiber

作　　者：涂义亮 张瑞[1,2] 任思雨 罗樟 蒋旭辉 王琦 王瑞琼 TU Yiliang;ZHANG Rui;REN Siyu;LUO Zhang;JIANG Xuhui;WANG Qi;WANG Ruiqiong(State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Institute of Environmental and Ecological Engineering,Power China Kunming Engineering Corporation Limited,Kunming Yunnan 650051,China;Engineering Technology Center,Power China Chongqing Engineering Corporation Limited,Chongqing 400060,China)

机构地区：[1]重庆交通大学省部共建山区桥梁及隧道工程国家重点实验室,重庆400074 [2]中国电建集团昆明勘测设计研究院有限公司环境与生态工程院,云南昆明650051 [3]中国电建集团重庆工程有限公司工程技术中心,重庆400060

出　　处：《中国铁道科学》2024年第1期36-46,共11页China Railway Science

基　　金：重庆市技术创新与应用发展专项项目(CSTB2022TIAD-GPX0046);重庆市南岸区技术创新与应用发展项目(2022-24);重庆市建设科技计划项目(城科字2022第1-3号)。

摘　　要：水泥土搅拌桩常用于处治山区软弱土路基,但其抗压强度和变形性能较弱,易发生脆性破坏。为此,提出采用玄武岩纤维提升水泥土搅拌桩抗压性能的方法,并通过单轴抗压试验分析纤维掺量和长度对玄武岩纤维水泥土抗压性能的影响规律,最后通过电镜扫描试验(SEM)揭示玄武岩纤维对水泥土的抗压性能提升机理。结果表明:玄武岩纤维水泥土的应力-应变曲线先后经历孔隙压密、弹性变形、弹塑性变形及破坏4个典型阶段;玄武岩纤维的掺入有效提高了水泥土的抗压性能,抗压强度、峰值应变随着纤维掺量的增加先增大后减小,弹性模量随之先减小后小幅上下波动;抗压强度随着纤维长度的增加而减小,峰值应变随之先增大后减小,而弹性模量则先减小后增大,在纤维掺量为0.6%、长度为6 mm时抗压强度最大;玄武岩纤维通过与水泥土颗粒之间的摩擦力和机械锚固力对土体进行摩擦加筋,锚固水泥土内部的裂纹增强颗粒之间的连接作用力,但当纤维过多或者较长时,会出现“堆聚”和“交叉搭接”现象,减少有效加筋纤维数量,从而降低试样的抗压性能,因此在水泥土中掺入玄武岩纤维时,纤维掺量和长度要适宜。Cement-soil mixing piles are often used to treat soft soil roadbeds in mountainous areas.However,weak compressive strength and deformation performance make them prone to brittle failure.Therefore,a method using basalt fibers to improve the compressive performance of cement-soil mixing piles is proposed in this study.Then,the influence of fiber content and length on the compressive performance of basalt fiber reinforced cement-soil is analyzed through a series of uniaxial compression tests.Finally,the mechanism of basalt fiber improving the compressive performance of cement-soil is revealed through several scanning electron microscope(SEM)tests.The results show that the stress-strain curves of basalt fiber reinforced cement-soil have undergone four typical stages:pore compaction,elastic deformation,elastic-plastic deformation,and failure.The addition of basalt fibers effectively improves the compressive performance of cement-soil.Its compressive strength and peak strain first increase and then decrease with the increase of fiber content,and the elastic modulus first decreases and then fluctuates slightly.As the fiber length increases,the compressive strength decreases,the peak strain first increases and then decreases,while the elastic modulus first decreases and then increases.When the fiber content is 0.6%and the length is 6 mm,the compressive strength reaches its maximum value.Basalt fibers reinforce the cement-soil through friction and anchoring force between the basalt fibers and the cement soil particles.This constrains the crack propagation inside the cement-soil and enhances the connecting force between the particles.However,the fibers will be stacking and cross overlapping when they are too much or too long in length.This phenomenon will reduce the number of effective reinforced fibers and thereby reducing the compressive performance of the sample.Therefore,when adding basalt fibers to cement-soil,the fiber content and length should be appropriate.

关 键 词：软弱土 玄武岩纤维 水泥土搅拌桩 单轴抗压试验 电镜扫描 

分 类 号：TU411.6[建筑科学—岩土工程]