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51.
To efficiently link the continuum mechanics for rocks with the structural statistics of rock masses,a theoretical and methodological system called the statistical mechanics of rock masses(SMRM)was developed in the past three decades.In SMRM,equivalent continuum models of stressestrain relationship,strength and failure probability for jointed rock masses were established,which were based on the geometric probability models characterising the rock mass structure.This follows the statistical physics,the continuum mechanics,the fracture mechanics and the weakest link hypothesis.A general constitutive model and complete stressestrain models under compressive and shear conditions were also developed as the derivatives of the SMRM theory.An SMRM calculation system was then developed to provide fast and precise solutions for parameter estimations of rock masses,such as full-direction rock quality designation(RQD),elastic modulus,Coulomb compressive strength,rock mass quality rating,and Poisson’s ratio and shear strength.The constitutive equations involved in SMRM were integrated into a FLAC3D based numerical module to apply for engineering rock masses.It is also capable of analysing the complete deformation of rock masses and active reinforcement of engineering rock masses.Examples of engineering applications of SMRM were presented,including a rock mass at QBT hydropower station in northwestern China,a dam slope of Zongo II hydropower station in D.R.Congo,an open-pit mine in Dexing,China,an underground powerhouse of Jinping I hydropower station in southwestern China,and a typical circular tunnel in Lanzhou-Chongqing railway,China.These applications verified the reliability of the SMRM and demonstrated its applicability to broad engineering issues associated with jointed rock masses. 相似文献
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For the purpose of providing references for further research and practical application about the quality improvement of RCA,in this paper,various treatment methods were firstly classified into four categories:removing old mortar (OM),strengthening OM,multi-stage mixing methods,and combination methods.Thereafter,the improvement mechanisms and important conclusions of various treatment methods were elucidated and summarised respectively.In the section of discussion,the improved effects as well as advantages and disadvantages of various treatment methods were compared and discussed respectively,and recommendations for the selection of treatment methods were proposed.Finally,the further research directions were pointed out,and an integrative programme on the quality improvement of RCA was recommended. 相似文献
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以钛酸四丁酯、氢氟酸和石墨棒为原料,采用简单的水热法将具有高催化活性的碳点负载在TiO_2纳米片的(001)晶面上,制得CDots-(001)TiO_2纳米片。通过TiO_2纳米片高催化活性的(001)晶面与碳点的协同作用,提高TiO 2纳米片的光吸收、载流子的传输和分离效率,从而有效提高材料的光催化产氢性能。紫外-可见漫反射吸收谱(UV-visDRS)、光致发光光谱(PL)、瞬态光响应分析结果表明,暴露(001)晶面的TiO_2纳米片负载碳点后,可见光吸收增强,光生载流子的分离和传输速率加快,在间歇模拟太阳光照射下,CDots-(001)TiO 2纳米片的光电流密度约为TiO 2的4倍,当碳点的负载量为2%时,CDots-(001)TiO 2纳米片的光催化产氢速率达5859μmol/(h·g),量子效率达9.6%。 相似文献
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侯文 《北京印刷学院学报》2021,29(5):78-81
英语语音学习中,学习者会遇到一些母语中不存在的二语音素,致使习得的时候经常出现困难和错误.本文从语音感知角度出发,引入语音感知同化模型理论,该理论描述二语习得者在习得不熟悉的二语音素时,会根据母语经验,在习得的过程中把这些音素归纳为与母语相似的音素.该研究通过实验设计识别任务和区分任务,分析中国学习者在习得/θ/和/e/时的感知倾向和其他影响因素,探索更有效的二语语音教学方法. 相似文献