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基于单柱齿破岩过程的高压液动冲击回转钻进试验研究 被引量:6
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作者 豆旭谦 姚宁平 +3 位作者 李秀山 王力 张凯 魏宏超 《煤田地质与勘探》 CAS CSCD 北大核心 2022年第12期170-176,共7页
针对煤矿井下穿层钻孔硬岩钻进效率低的难题,基于冲击回转钻进机理和Wassara高压液动冲击器主要特点,分析柱齿在冲击荷载下形成的破碎坑形态,并将其划分为崩解区、密实区、开裂区和弹性区。在此基础之上,对柱齿连续破岩的大间隔冲击和... 针对煤矿井下穿层钻孔硬岩钻进效率低的难题,基于冲击回转钻进机理和Wassara高压液动冲击器主要特点,分析柱齿在冲击荷载下形成的破碎坑形态,并将其划分为崩解区、密实区、开裂区和弹性区。在此基础之上,对柱齿连续破岩的大间隔冲击和小间隔冲击2种情况进行过程分析,结合淮南潘三矿现场试验条件讨论高压液动冲击回转钻进工艺参数,优选高压液动冲击回转钻进配套钻机、冲击器、钻杆、钻头和清水泵,及主要技术参数。试验结果表明:当清水压力在15 MPa以上时,高压液动冲击回转钻进的平均机械钻速为24.67 m/h,与采用该技术之前的8.48 m/h机械钻速相比提高了约1.9倍;并采用回归分析拟合得到机械钻速与水压之间的线性关系,经过数理统计的F检验,F=8.82大于F_(0.05)(1,7),验证了回归结果是显著的,机械钻速随水压的增大而线性增大。高压液动冲击回转钻进技术可有效提高煤矿井下硬岩层钻进效率,保障煤矿安全高效生产。 展开更多
关键词 单齿柱 连续破岩 高压液动冲击器 冲击回转钻进 钻进
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Effects of discontinuities on penetration of TBM cutters 被引量:2
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作者 刘杰 曹平 +2 位作者 杜春黄 蒋喆 刘京铄 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3624-3632,共9页
Based on the triaxial testing machine and discrete element method, the effects of embedded crack on rock fragmentation are investigated in laboratory tests and a series of numerical investigations are conducted on the... Based on the triaxial testing machine and discrete element method, the effects of embedded crack on rock fragmentation are investigated in laboratory tests and a series of numerical investigations are conducted on the effects of discontinuities on cutting characteristics and cutting efficiency. In laboratory tests, five propagation patterns of radial cracks are observed. And in the numerical tests, firstly, it is similar to laboratory tests that cracks ahead of cutters mainly initiate from the crushed zone, and some minor cracks will initiate from joints. The cracks initiating from crushed zones will run through the thinner joints while they will be held back by thick joints. Cracks tend to propagate towards the tips of embedded cracks, and minor cracks will initiate from the tips of embedded cracks, which may result in the decrease of specific area, and disturbing layers play as ‘screens', which will prevent cracks from developing greatly. The peak penetration forces, the consumed energy in the penetration process and the uniaxial compression strength will decrease with the increase of discontinuities. The existence of discontinuities will result in the decrease of the cutting efficiency when the spacing between cutters is 70 mm. Some modifications should be made to improve the efficiency when the rocks containing groups of discontinuities are encountered. 展开更多
关键词 tunnel boring machine(TBM) cutter triaxial testing machine numerical model DISCONTINUITY cutting characteristic cutting efficiency
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Geotechnical stability analysis considering strain softening using micro-polar continuum finite element method 被引量:5
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作者 CHEN Xi WANG Dong-yong +2 位作者 TANG Jian-bin MA Wen-chen LIU Yong 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第1期297-310,共14页
Geotechnical stability analyses based on classical continuum may lead to remarkable underestimations on geotechnical safety.To attain better estimations on geotechnical stability,the micro-polar continuum is employed ... Geotechnical stability analyses based on classical continuum may lead to remarkable underestimations on geotechnical safety.To attain better estimations on geotechnical stability,the micro-polar continuum is employed so that its internal characteristic length(lc)can be utilized to model the shear band width.Based on two soil slope examples,the role of internal characteristic length in modeling the shear band width of geomaterial is investigated by the second-order cone programming optimized micro-polar continuum finite element method.It is recognized that the underestimation on factor of safety(FOS)calculated from the classical continuum tends to be more pronounced with the increase of lc.When the micro-polar continuum is applied,the shear band dominated by lc is almost kept unaffected as long as the adopted meshes are fine enough,but it does not generally present a slip surface like in the cases from the classical continuum,indicating that the micro-polar continuum is capable of capturing the non-local geotechnical failure characteristic.Due to the coupling effects of lc and strain softening,softening behavior of geomaterial tends to be postponed.Additionally,the bearing capacity of a geotechnical system may be significantly underestimated,if the effects of lc are not modeled or considered in numerical analyses. 展开更多
关键词 slope stability strain localization non-local geotechnical failure micro-polar continuum internal characteristic length
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Discontinuous deformation and displacement analysis: From continuous to discontinuous 被引量:6
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作者 TANG ChunAn TANG ShiBin +1 位作者 GONG Bin BAI HongMei 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第9期1567-1574,共8页
A discontinuous deformation and displacement(DDD) analysis method is proposed for modelling the rock failure process. This method combines the rock failure process analysis(RFPA) method(based on finite element method)... A discontinuous deformation and displacement(DDD) analysis method is proposed for modelling the rock failure process. This method combines the rock failure process analysis(RFPA) method(based on finite element method) and discontinuous deformation analysis(DDA) method. RFPA is used to simulate crack initiation, propagation and coalescence processes of rock during the small deformation state. The DDA method is used to simulate the movement of blocks created by the multiple cracks modelled by the RFPA. The newly developed DDD method is particularly suitable for modelling both crack propagation and block movement during the rock failure process because of the natural and convenient coupling of continuous and discontinuous deformation analyses. The proposed method has been used to simulate crack initiation, propagation and coalescence within a slope as well as the block movement during the landslide process. Numerical modelling results indicate that the proposed DDD method can automatically simulate crack propagation and block movement during the rock failure process without degrading accuracy. 展开更多
关键词 rock failure process finite element method discontinuous deformation analysis (DDA) crack propagation slope stability
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