天津大学学报
天津大學學報
천진대학학보
JOURNAL OF TIANJIN UNIVERSITY SCIENCE AND TECHNOLOGY
2013年
7期
596-602
,共7页
砂土%应变软化%应变局部化%剪切带%盾构%掘进界面失稳
砂土%應變軟化%應變跼部化%剪切帶%盾構%掘進界麵失穩
사토%응변연화%응변국부화%전절대%순구%굴진계면실은
sand%strain-softening%strain localization%shear band%shield%instability of tunneling face
岩土工程中的许多土体有应变软化行为，这种软化行为能导致应变局部化，进而对土体的稳定性有重要影响。首先研究饱和砂土的排水平面应变压缩试验的剪切带的形成，进行数值分析，预测了实验现象。然后，考虑土体应变软化盾构掘进面失稳的影响，对深埋隧道的盾构掘进进行三维数值分析，对比分析渗流条件下应变硬化模型和应变软化模型以及应变软化条件下考虑渗流与未考虑渗流模型之间的区别。分析表明，土体应变软化更容易导致盾构掘进界面失稳，使得开挖面的极限支护压力和地表沉降增大、塑性区扩展比没有应变软化的土体更大。探讨了诸如内摩擦角、黏聚力等土质应变软化参数的变化对盾构掘进界面稳定性的影响，发现内摩擦角软化的影响较大，黏聚力次之。最后，对天津地铁9号线的一段盾构掘进进行了模拟，其结果与工程实测数据相吻合。
巖土工程中的許多土體有應變軟化行為，這種軟化行為能導緻應變跼部化，進而對土體的穩定性有重要影響。首先研究飽和砂土的排水平麵應變壓縮試驗的剪切帶的形成，進行數值分析，預測瞭實驗現象。然後，攷慮土體應變軟化盾構掘進麵失穩的影響，對深埋隧道的盾構掘進進行三維數值分析，對比分析滲流條件下應變硬化模型和應變軟化模型以及應變軟化條件下攷慮滲流與未攷慮滲流模型之間的區彆。分析錶明，土體應變軟化更容易導緻盾構掘進界麵失穩，使得開挖麵的極限支護壓力和地錶沉降增大、塑性區擴展比沒有應變軟化的土體更大。探討瞭諸如內摩抆角、黏聚力等土質應變軟化參數的變化對盾構掘進界麵穩定性的影響，髮現內摩抆角軟化的影響較大，黏聚力次之。最後，對天津地鐵9號線的一段盾構掘進進行瞭模擬，其結果與工程實測數據相吻閤。
암토공정중적허다토체유응변연화행위，저충연화행위능도치응변국부화，진이대토체적은정성유중요영향。수선연구포화사토적배수평면응변압축시험적전절대적형성，진행수치분석，예측료실험현상。연후，고필토체응변연화순구굴진면실은적영향，대심매수도적순구굴진진행삼유수치분석，대비분석삼류조건하응변경화모형화응변연화모형이급응변연화조건하고필삼류여미고필삼류모형지간적구별。분석표명，토체응변연화경용역도치순구굴진계면실은，사득개알면적겁한지호압력화지표침강증대、소성구확전비몰유응변연화적토체경대。탐토료제여내마찰각、점취력등토질응변연화삼수적변화대순구굴진계면은정성적영향，발현내마찰각연화적영향교대，점취력차지。최후，대천진지철9호선적일단순구굴진진행료모의，기결과여공정실측수거상문합。
Many kinds of soil in geotechnical engineering display strain-softening behavior ,which can result in strain localization and, furthermore, the instability of soil. On the basis of the local strain fields in the specimen obtained from the drained plane strain compression test on saturated sand, the paper first makes a numerical analysis to predict the experimental phenomenon. Then, the strain-softening influence of shield excavation surface instability is consid-ered, three-dimensional numerical simulation for deep shield tunneling is performed, and the strain hardening and sof-tening models in the condition of seepage are compared, so are the seepage and non-seepage models in the condition of strain softening. The analysis shows that, compared with soil without strain-softening behavior, the strain-softening of soil more easily causes the instability of shield tunneling face, increases the limits of face pressure and the settle-ment of the ground, and leads to more expansion of plastic regime. How the change of the values of strain-softening parameters, such as internal friction angle and cohesion, affects the instability of shield tunneling face is discussed, and it is found that internal friction angle has a great influence, followed by cohesion. Finally, the shield tunneling in a section of Tianjin Metro Line 9 is simulated, and the results are consistent with the measured data.
