在兰新铁路第二双线一处典型泥岩地基工点处,采用开挖不同深度浸水孔并施加上部荷载方法,进行3个试验基坑的泥岩地基原位浸水膨胀变形试验,分别研究在9.75,21.44,38.99,58.48,65.31,77.99 k Pa六种上覆荷载情况下,以及0.7,1.1,1.5 m三...在兰新铁路第二双线一处典型泥岩地基工点处,采用开挖不同深度浸水孔并施加上部荷载方法,进行3个试验基坑的泥岩地基原位浸水膨胀变形试验,分别研究在9.75,21.44,38.99,58.48,65.31,77.99 k Pa六种上覆荷载情况下,以及0.7,1.1,1.5 m三种浸水深度情况下,泥岩地基的膨胀变形特性。结果表明:泥岩浸水膨胀变形表现为短暂软化沉降、膨胀骤增、膨胀减缓、膨胀平衡稳定4个阶段;得出不同浸水深度与膨胀变形值为非线性关系;在浸水孔深度1.5 m,上部荷载9.75 k Pa时,地基最大膨胀量约41 mm;在上覆荷载值一定的情况下,浸水后地基泥岩含水率会达到最大限值,约14%,且浸水量不会随着外界水分补给而增大;当泥岩内部含水率在限值范围内增大时,会储存有膨胀能,在上覆荷载减小或浸水深度增大的情况下,泥岩地基以稍滞后的膨胀变形体现出其膨胀能;拟合得出泥岩地基膨胀量与上覆荷载的非线性关系曲线及关系式;总结泥岩加荷–浸水膨胀以塑性变形为主,卸载情况下泥岩的回弹量值占总变形量的6.39%~7.00%。展开更多
A kind of micro/nanostructured 2205 duplex stainless steel(DSS)with uniform distribution of nanocrystals was prepared via aluminothermic reaction method.The analysis of stress-strain curve showed that the fracture str...A kind of micro/nanostructured 2205 duplex stainless steel(DSS)with uniform distribution of nanocrystals was prepared via aluminothermic reaction method.The analysis of stress-strain curve showed that the fracture strength and elongation of the specimen were 946 MPa and 24.7%,respectively.At present,the research on microstructure of bimodal 2205 DSS at room temperature(RT)mainly depended on scanning electron microscope(SEM)observation after loading experiments.The test result indicates that there are two different yield stages in stress-strain curve of specimen during tensile process.The microstructure of duplex bimodal structured stainless steel consists of two pairs of soft hard regions and phases.By studying deformation mechanism of bimodal structured stainless steel,the interaction between soft phase and hard phase are discussed.The principle of composition design and microstructure control of typical duplex stainless steel is obtained,which provides an important research basis for designing of advanced duplex stainless steel.展开更多
文摘在兰新铁路第二双线一处典型泥岩地基工点处,采用开挖不同深度浸水孔并施加上部荷载方法,进行3个试验基坑的泥岩地基原位浸水膨胀变形试验,分别研究在9.75,21.44,38.99,58.48,65.31,77.99 k Pa六种上覆荷载情况下,以及0.7,1.1,1.5 m三种浸水深度情况下,泥岩地基的膨胀变形特性。结果表明:泥岩浸水膨胀变形表现为短暂软化沉降、膨胀骤增、膨胀减缓、膨胀平衡稳定4个阶段;得出不同浸水深度与膨胀变形值为非线性关系;在浸水孔深度1.5 m,上部荷载9.75 k Pa时,地基最大膨胀量约41 mm;在上覆荷载值一定的情况下,浸水后地基泥岩含水率会达到最大限值,约14%,且浸水量不会随着外界水分补给而增大;当泥岩内部含水率在限值范围内增大时,会储存有膨胀能,在上覆荷载减小或浸水深度增大的情况下,泥岩地基以稍滞后的膨胀变形体现出其膨胀能;拟合得出泥岩地基膨胀量与上覆荷载的非线性关系曲线及关系式;总结泥岩加荷–浸水膨胀以塑性变形为主,卸载情况下泥岩的回弹量值占总变形量的6.39%~7.00%。
基金Funded by the National Natural Science Foundation of China(No.51911530119)the Department of Education of Gansu Province Innovation Fund(No.2021A-023)the Open Fund Project of Key Laboratory of Solar Power System Engineering Project(No.2022SPKL01)。
文摘A kind of micro/nanostructured 2205 duplex stainless steel(DSS)with uniform distribution of nanocrystals was prepared via aluminothermic reaction method.The analysis of stress-strain curve showed that the fracture strength and elongation of the specimen were 946 MPa and 24.7%,respectively.At present,the research on microstructure of bimodal 2205 DSS at room temperature(RT)mainly depended on scanning electron microscope(SEM)observation after loading experiments.The test result indicates that there are two different yield stages in stress-strain curve of specimen during tensile process.The microstructure of duplex bimodal structured stainless steel consists of two pairs of soft hard regions and phases.By studying deformation mechanism of bimodal structured stainless steel,the interaction between soft phase and hard phase are discussed.The principle of composition design and microstructure control of typical duplex stainless steel is obtained,which provides an important research basis for designing of advanced duplex stainless steel.
