CAJ | 학술논문

天津滨海软土力学性质较差，不能直接满足工程需要，在软土中加入固化剂能有效提高软土的工程力学性能，但若在固化剂中再添加适量外加剂，又能再次提高固化土的强度。本文以石灰作为主剂，水泥、石膏作为辅剂改良天津滨海软土，以无侧限抗压强度作为固化效果判断标准，同时进行相应的微观结构测试，并对破坏后的试样进行抗压试验。试验结果表明：水泥的最佳掺量仅随石灰掺量不同而变化，如12％的石灰固化土中，水泥掺量不超过3％可以最好地提高石灰固化土强度；石膏则不能改善土体强度，并且会使土体水稳定性差，遇水开裂。纯石灰固化土及掺外加剂的石灰固化土都是低压缩性土，各种力学性质都得到明显提高，其破坏形式为脆性破坏，破坏后强度很低且不能恢复，在实践中值得重视。微观结构分析表明：固化土中有 C—S—H 网状胶凝（水化硅酸钙）、针状钙矾石、无定形文石（CaCO3）、Ca（OH）2晶体等能够填充孔隙、胶结颗粒的物质生成，有效、适量的生成物有利于固化土强度的提高。土体中总孔隙个数及总颗粒个数都随荷载的增加而增多，孔隙面积、孔隙等效直径及颗粒等效直径都随荷载的增加而减少。
천진빈해연토역학성질교차，불능직접만족공정수요，재연토중가입고화제능유효제고연토적공정역학성능，단약재고화제중재첨가괄량외가제，우능재차제고고화토적강도。본문이석회작위주제，수니、석고작위보제개량천진빈해연토，이무측한항압강도작위고화효과판단표준，동시진행상응적미관결구측시，병대파배후적시양진행항압시험。시험결과표명：수니적최가참량부수석회참량불동이변화，여12％적석회고화토중，수니참량불초과3％가이최호지제고석회고화토강도；석고칙불능개선토체강도，병차회사토체수은정성차，우수개렬。순석회고화토급참외가제적석회고화토도시저압축성토，각충역학성질도득도명현제고，기파배형식위취성파배，파배후강도흔저차불능회복，재실천중치득중시。미관결구분석표명：고화토중유 C—S—H 망상효응（수화규산개）、침상개반석、무정형문석（CaCO3）、Ca（OH）2정체등능구전충공극、효결과립적물질생성，유효、괄량적생성물유리우고화토강도적제고。토체중총공극개수급총과립개수도수하재적증가이증다，공극면적、공극등효직경급과립등효직경도수하재적증가이감소。
The mechanical behavior of Tianjin marine soft soil cant meet the requirement of engineering construction,but it can be enhanced effectively by curing agents.Moreover when curing agents and additional agent are added in the soft soil together,the strength of the stabilized soil can be improved further.For this reason,the method of combing lime and cement or gypsum is proposed in this paper.In the test the unconfined compressive strength of solidified soil is used as a criterion to identify the solidifying effect.Meanwhile,sample microstructure is analyzed with SEM and the unconfined compressive strength of destroyed and re-cured samples is measured and recorded.Test and analysis results indicate that the optimum content of cement only changes with the different dosage of lime.For example,if the content of cement in stabilized soil adding 12%lime is less than 3%,the effect of solidification is the best.Gypsum cant improve the soil strength.It even makes the water stability of soil badly and causes the soil crack under the influence of water.Although the compressibility of both lime stabilized soil with and without additional agent is low,their various mechanical properties can be improved obviously.Their failure mode is the brittle failure.The strength of destroyed soil is very low and cant recovery,to which attention should be given in practice.Microstructure analysis shows that the C -S -H(hydrated calcium silicate),acicular ettringite, CaCO3 and Ca(OH)2 crystal formed in soil can fill pores and cement particles.Effective and proper product is beneficial to improve the strength of stabilized soil.The total of pores and particles in solidified soil increases with the augment of the pressure,however,area of pore,equivalent diameter of both pores and particles decreases with the augment of pressure.