\r加 瑞^{1, 2}，雷华阳^{1, 2}，冯双喜^{1, 2}

AuthorsHTML:\r加 瑞^{1, 2}，雷华阳^{1, 2}，冯双喜^{1, 2}

AuthorsListE:\rJia Rui^{1, 2}，Lei Huayang^{1, 2}，Feng Shuangxi^{1, 2}

AuthorsHTMLE:\rJia Rui^{1, 2}，Lei Huayang^{1, 2}，Feng Shuangxi^{1, 2}

Unit:\r1. 天津大学建筑工程学院，天津 300350；
2. 天津大学滨海土木工程结构与安全教育部重点实验室，天津 300350

Unit_EngLish:\r1. School of Civil Engineering，Tianjin University，Tianjin 300350，China；
2. Key Laboratory of Coast Civil Structure Safety of Ministry of Education，Tianjin University，Tianjin 300350，China

Abstract_Chinese:\r温度改变会影响孔压静力触探(CPTU)的测量结果．利用CPTU 调查了海底泥的特性，由于海底泥的锥尖阻力(q_c)和侧壁摩阻力(f_s)较小而且调查时海底泥和海水中的温差较大，f_s 大多数是负值且随深度逐渐减小．据此提出了在没有安装温度传感器的情况下考虑温度对CPTU 在海底泥中测试结果影响的修正方法：首先通过室内温度校正试验获得q_c和f_s的温度校正系数；然后假设浅层海底泥的fs随深度线性增加，根据相关测量结果或经验估计“实际”的f_s剖面；再根据测量和“实际”的f_s剖面的区别估计地基中的温度剖面；最后根据温度剖面和温度校正系数对CPTU 的测量结果进行温度修正．对本文CPTU 测试数据的温度修正结果表明，如果不考虑温度的影响，CPTU在海底泥中的f_s会被低估，其值会随深度减小甚至变为负值；在约3.5 m 深度处，海底泥的q_t(考虑孔压修正的锥尖阻力)可能会被高估50%以上；海底泥的不排水抗剪强度(s_u)将会被高估，温度修正后CPTU 所得s_u更接近于室内试验所得的s_u．在本文所建议的修正方法中，唯一不确定的参数是正常固结海底沉积物的f_s 随深度的增加率(α)．本文通过反分析得出的α＝0.2 kPa/m，黏土矿物类型和沉积环境等因素可能会影响α的大小．实际中应该根据相关的测量数据确定α的大小，如果没有相关的测量数据，可以采用本文建议的α值．

Abstract_English:\rThe measurement results of the piezocone penetration test(CPTU)are influenced by temperature．In this study，we used the CPTU to investigate the properties of seabed sediments．We found that the values of sleeve friction(f_s)were generally negative and decreased with ncreasing depth owing to the lower values of the cone resistance(q_c)and f_s in seabed sediments and the greater temperature difference between the seabed sediments and seawater．We propose a correction method for considering the temperature effect on CPTU measurements in seabed sediments for cases in which there is no temperature sensor in the CPTU probe．First，we obtain the temperature correction factors of f_s and qc through laboratory temperature calibration testing. Then，we estimate the “actual” f_s profile according to the local experience or measured data based on the assumption that the f_s value of shallow seabed sediments linearly increases with depth．Then，we estimate the ground temperature profile based on the difference between the measured and “actual” f_s profiles. Finally，we correct the CPTU easurements based on the ground temperature profile and temperature correction factors．The temperature correction results for the CPTU measurements in this study show that if temperature correction had not been performed，the fs values of seabed sediments might have been underestimated．Further，we found that the values of fs generally decreased with increasing depth and became negative．In addition，the q_t values might have been overestimated by more than 50% at a depth of approximately 3.5 m，the undrained shear strength(s_u)values might have been overestimated，and the corrected CPTU measured s_u values were comparable with those measured in the laboratory．In the proposed method，the only uncertain key parameter is the rate of increase of f_s with depth(α)of normally consolidated young seabed deposits．For this case study，we back-calculated α＝0.2 kPa/m．The value of α may change with the deposit environment and type of clay mineral．The value of α should be determined based on the available measured data，but if there are no directly measured data for determining the value of α，the proposed value of α in this study can be adopted．

Keyword_Chinese:孔压静力触探(CPTU)；海底泥；温度修正方法；地基温度

Keywords_English:piezocone penetration test(CPTU)；seabed sediments；temperature correction method；ground temperature


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