旋压入土式静力触探机制研究
详细信息 本馆镜像全文    |  推荐本文 | | 获取馆网全文
摘要
由于现有静力触探机械设备提供的动力有限,使得静力触探技术无法应用于较硬土层或较深土层中(应力较高)。保证探头顺利平稳地探入较硬土层,是触探技术应用于硬土层的前提条件。通过对旋压式触探时探头上的受力进行分析,推导了不考虑侧壁摩擦力的旋压式触探的总锥尖阻力和扭矩的理论模型,同时也推导了用旋压式触探测试成果计算锥土间摩擦系数的数学模型,并在室内旋压式触探仪上进行相应的试验,试验结果不仅验证了理论分析的正确性,而且试验结果表明:对同一土体制成不同含水率、干重度的试样进行相同的探入速度和旋转速度下的旋压式触探,所得的扭矩与总锥尖阻力呈线性关系。根据数学模型计算的锥土间摩擦系数要比土体的内摩擦系数大得多,但两者具有较明显的一致性。结合土层的各向异性的特点、锥土间的摩阻力的存在等因素分析了旋压式触探方式能够降低总锥尖阻力的原因。
The cone penetration test(CPT) can't be used in harder soil such as loess or in deeper soil because of the higher cone resistance and the limited capacity of the equipment of CPT.Cone's being smoothly pushed into the ground is prerequisite for applying probing technologies in harder or deeper soil.By theoretically analyzing the forces on the cone,the theoretical equations of total cone resistance and torque,excluding wall sided frictional resistance,is established,in which all the influence factors are given.Meantime the mathematic equation to determine the friction coefficient between the soil and the cone is deduced from the theoretical equations of total cone resistance and torque.In addition,the laboratory rotary cone penetration test(RCPT) is carried out.The validity of theoretical analysis is proved.According to the results of RCPT for the samples with different water contents and different dry densities,linear relationship exists between the toque and the total cone resistance on the cone.Although the calculated value of friction coefficient between the soil and the cone based on the results of RCPT is much greater than that of internal friction coefficient of soil,its relevance to the internal friction coefficient of soil appears in some extend.The reason why the lower total resistance acts on the cone when the cone is simultaneously pushed and rotated than that when being only pushed is given by taking account of property along the vertical different from that in the horizon plane of soil and existence of frictional resistance between the cone and soil.
引文
[1]吴道祥,单灿灿,钟轩明,等.静力触探的发展及其在岩土工程中的应用[J].合肥工业大学学报(自然科学版),2008,31(2):211-215.WU Dao-xiang,SHAN Can-can,ZHONG Xuan-ming,etal.Development of CPT and its application ingeotechnical engineering[J].Journal of Hefei Universityof Technology,2008,31(2):211-215.
    [2]崔新壮,丁桦,金青,等.微型触探仪的研制与粉质粘土中的静力触探试验研究[J].实验力学,2005,20(2):207-212.CUI Xin-zhuang,DING Hua,JIN Qing,et al.Development of miniature cone penetrometer and studyon MCPT in silty clay[J].Journal of ExperimentalMechanics,2005,20(2):207-212.
    [3]施斌,刘志彬,蔡奕.超微型贯入仪的研制及其应用[J].岩土力学,2005,26(8):1211-1215.SHI Bin,LIU Zhi-bin,CAI Yi.Development of the supermini-penetrometer and its application[J].Rock and SoilMechanics,2005,26(8):1211-1215.
    [4]建设部综合勘察研究院,同济大学.CECS04:88静力触探技术标准[S].北京:中国建筑标准化委员会出版社,1989.
    [5]李宁,宋玲,刘奉银.围岩力学参数现场测试系统[P].中国:200810236566.9,2008-12-31.
    [6]毛玉坤,刘奉银,李宁,等.CPT理论分析及提高触探能力的新思路[J].西北地震学报,2007,29(1):40-44.MAO Yu-kun,LIU Feng-yin,LI Ning,et al.CPT theoryanalysis and a new idea for improving penetrationcapability[J].Northwestern Seismological Journal,2007,29(1):40-44.
    [7]刘奉银,罗士梅,李宁.西安黄土的新型旋转触探室内试验研究[J].西安理工大学学报,2008,24(3):316-319.LIU Feng-yin,LUO Shi-mei,LI Ning.The lab.experimental research on Xi'an Loess with a newapparatus of rotary penetration[J].Journal of Xi'an University of Technology,2008,24(3):316-319.
    [8]罗士梅.新型旋转触探仪在坚硬黄土中应用的试验研究[硕士学位论文D].西安:西安理工大学,2008.
    [9]孟高头,鲁少宏,姜珂.静力触探机理研究[J].地球科学—中国地质大学学报,1997,22(4):419-423.MENG Gao-tou,LU Shao-hong,JIANG Ke.A study onmechanism of cone penetration test[J].Earth Science—Journal of China University of Geosciences,1997,22(4):419-423.
    [10]谢定义,姚仰平,党发宁.高等土力学[M].北京:高等教育出版社,2008.

版权所有:© 2023 中国地质图书馆 中国地质调查局地学文献中心