岩土工程学报
巖土工程學報
암토공정학보
CHINESE JOURNAL OF GEOTECHNICAL ENGINEERING
2015年
4期
608-614
,共7页
粗粒土%冻融循环%细粒含量%应力-应变关系%抗剪强度指标
粗粒土%凍融循環%細粒含量%應力-應變關繫%抗剪彊度指標
조립토%동융순배%세립함량%응력-응변관계%항전강도지표
coarse-grained soil%freeze-thaw cycle%fines content%stress-strain relationship%shear strength index
以粗粒土填料在冻土地区铁路路基中的应用和推广为研究背景，针对冻融作用及细粒含量对粗粒土填筑路基稳定性的影响，通过室内三轴试验深入研究和分析了冻融次数、细粒含量以及围压对粗粒土试样强度特性的影响规律。研究结果表明，随着细粒含量的增加，粗粒土的应力应变曲线由冻融前的应变软化现象过渡到冻融后的应变硬化现象；同时，随着细粒含量的增加，未经历冻融时，细粒土的黏结性有效地提高了粗粒土的剪切强度，而经历冻融后，细粒土的冻胀性反而削弱了粗粒土的剪切强度；粗粒土的剪切强度和抗剪强度指标随冻融次数的增加而减小并在经历6次冻融后达到稳定状态；围压的“围箍”作用有效地提高了粗粒土的抗剪强度；通过讨论和分析，建议冻土区铁路路基粗粒土填料的合理细粒含量为5%，并将粗粒土填料经历6次冻融后的力学指标作为工程设计值。
以粗粒土填料在凍土地區鐵路路基中的應用和推廣為研究揹景，針對凍融作用及細粒含量對粗粒土填築路基穩定性的影響，通過室內三軸試驗深入研究和分析瞭凍融次數、細粒含量以及圍壓對粗粒土試樣彊度特性的影響規律。研究結果錶明，隨著細粒含量的增加，粗粒土的應力應變麯線由凍融前的應變軟化現象過渡到凍融後的應變硬化現象；同時，隨著細粒含量的增加，未經歷凍融時，細粒土的黏結性有效地提高瞭粗粒土的剪切彊度，而經歷凍融後，細粒土的凍脹性反而削弱瞭粗粒土的剪切彊度；粗粒土的剪切彊度和抗剪彊度指標隨凍融次數的增加而減小併在經歷6次凍融後達到穩定狀態；圍壓的“圍箍”作用有效地提高瞭粗粒土的抗剪彊度；通過討論和分析，建議凍土區鐵路路基粗粒土填料的閤理細粒含量為5%，併將粗粒土填料經歷6次凍融後的力學指標作為工程設計值。
이조립토전료재동토지구철로로기중적응용화추엄위연구배경，침대동융작용급세립함량대조립토전축로기은정성적영향，통과실내삼축시험심입연구화분석료동융차수、세립함량이급위압대조립토시양강도특성적영향규률。연구결과표명，수착세립함량적증가，조립토적응력응변곡선유동융전적응변연화현상과도도동융후적응변경화현상；동시，수착세립함량적증가，미경력동융시，세립토적점결성유효지제고료조립토적전절강도，이경력동융후，세립토적동창성반이삭약료조립토적전절강도；조립토적전절강도화항전강도지표수동융차수적증가이감소병재경력6차동융후체도은정상태；위압적“위고”작용유효지제고료조립토적항전강도；통과토론화분석，건의동토구철로로기조립토전료적합리세립함량위5%，병장조립토전료경력6차동융후적역학지표작위공정설계치。
For the promotion and application of coarse-grained soil fillings in the railway subgrade in frozen regions, the shear strength properties of coarse-grained soil with fines content under freeze-thaw cycles are directly related to the subgrade stability. The influencing rules of freeze-thaw cycles, fines content and confining pressure on the shear strength properties of coarse-grained soil are therefore thoroughly studied and analyzed in laboratory tests. The results show that with the increasing increment of fines content, the stress-strain curve of coarse-grained soil changes from strain-softening before freeze-thaw cycles to strain-hardening after freeze-thaw cycles. With the increasing of fines content, the cohesion function of fines effectively enhances the shear strength of coarse-grained soil before freeze-thaw cycles, but the frost heave properties of fines decrease the shear strength of coarse-grained soil after freeze-thaw cycles. The shear strength indexes of coarse-grained soil decrease and then are steady after 6 freeze-thaw cycles. The confining pressure effectively enhances the shear strength of coarse-grained soil. Finally, the reasonable fines content of 5% is recommended for the railway subgrade coarse-grained soil fillings in frozen regions, and the mechanical indexes of the 6th freeze-thaw cycle are suggested for the engineering design values.
