首页|膨胀土流态固化改性试验与配合比研究

膨胀土流态固化改性试验与配合比研究

Fluidized solidification modification tests on expansive soil and its mixing proportions study

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流态固化改性是弃方资源化新方式,有助于解决道路工程中异形或狭隘空间难以回填压实问题.选取南宁地区中等膨胀土弃方,与水、水泥及标准砂混合配制流态固化土试样并开展室内土工试验,分析掺配比对试样膨胀性、强度、流动度及泌水率的影响规律.结果表明:试样膨胀性由掺灰比和掺砂比决定,受水固比影响小,当掺灰比大于 18%且掺砂比超过 6%时,试样呈现非膨胀特征.无侧限抗压强度主要来自水泥水化作用,随掺砂比的增加呈先增大后降低的变化,掺砂比上限宜控制在 10%;水固比增加导致强度大幅下降,水固比大于 80%后干湿循环条件下的强度衰减趋势显著.初始流动度与水固比、掺砂比及掺灰比正相关,受掺灰比影响最小;试样拌合完成后的 90 min是流动度损失的主要阶段,流动度损失率为 23%~32%,随后变化放缓.泌水率取决于水固比,受掺灰比影响较小.基于试验规律,经归一化分析得到膨胀土流态固化改性配合比设计流程.
Fluidized solidification modification constitutes a new method for repurposing discarded materials,offering a solution to challenges associated with backfill compaction in irregular or constrained spaces within road engineering.Employing a distinct variety of medium expansive soil from the Nanning region,and amalgamating it with water,cement,and standardized sand,fluidized solidified soil specimens were developed and evaluated through laboratory-scale geotechnical examinations.The implications of diverse mixing proportions on swelling potential,strength,fluidity and bleeding rate of the specimens were comprehensively analyzed.Results show that the swelling characteristic of the specimens is largely contingent upon the cement-to-aggregate ratio and the sand-to-soil ratio,while the water-to-solid ratio exerts a minimal effect.The specimens manifest non-expansive characteristics when the cement-to-aggregate ratio exceeds 18%and the sand-to-soil ratio surpasses 6%.The unconfined compressive strength primarily emanates from the cement-to-aggregate ratio,exhibiting an initial increase followed by a decline with an augmented sand-to-soil ratio,necessitating sand-to-soil ratio control within 10%.An elevation in the water-to-solid ratio substantially attenuates the strength,with a ratio exceeding 80%markedly accelerating the strength degradation under cyclical wet-dry conditions.Initial fluidity is positively correlated with the water-to-solid ratio,sand-to-soil ratio and cement-to-aggregate ratio,and is least affected by the cement-to-aggregate ratio.The 90 min after the specimen finished mixing is the main stage of fluidity loss,with the rate of fluidity loss ranging from 23%to 32%,and then the change slows down.The bleeding rate is controlled by the water-to-solid ratio and is less affected by the cement-to-aggregate ratio.Based on the experimental pattern,the proportion design process for fluidized solidification modification of expansive soils was derived through data normalization analysis.

expansive soilfluidized solidified soilswelling potentialunconfined compressive strengthfluiditymixing proportion

杜建彪、罗强、蒋良潍、曹子奇、王腾飞、张良

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西南交通大学土木工程学院,四川成都 610031

西南交通大学高速铁路线路工程教育部重点实验室,四川成都 610031

中电建铁路建设投资集团有限公司,北京 100071

膨胀土 流态固化土 膨胀性 无侧限抗压强度 流动度 配合比

2024

浙江大学学报(工学版)
浙江大学

浙江大学学报(工学版)

CSTPCD北大核心
影响因子:0.625
ISSN:1008-973X
年,卷(期):2024.58(10)