基于旁压试验的白沙井组网纹红土力学参数分析  

Study on the Geotechnical Characteristics of the Reticulate Red Soil of Baishajing Formation Based on the Pressuremeter Test

作　　者：彭柏兴 PENG Baixing(Changsha Municipal Institute of Investigation and Design,Changsha 410007,China)

机构地区：[1]长沙市勘测设计研究院,湖南长沙410007

出　　处：《城市勘测》2025年第2期209-216,共8页Urban Geotechnical Investigation & Surveying

摘　　要：预钻式旁压试验具有对土体扰动小、适应能力强、成果直观等特点,有效规避了取样扰动和室内外应力状态的差异,是合理认识网纹状粉质黏土强度特征的有效手段。以湘江二级阶地上某工程为例,通过2个钻孔的预钻式旁压试验,获得了网纹红土不同深度的P-V曲线,求得其初始压力、临塑压力及极限压力,并计算相应的旁压模量、似变形模量、地基承载力特征值等力学特性参数。针对旁压曲线及其3个特征压力值和2个特征强度指标,以及压缩模量E s和地基承载力与其埋深展开相关性分析,发现网纹红土的相关力学参数并非随深度增大而逐渐增大,而是与其状态密切相关。通过与相邻场地的载荷试验成果进行了对比分析发现,旁压试验获得的地基承载力特征值与载荷试验结果相近、高于理论公式计算值与标准贯入试验的结果。该结果可供类似工程参考。The pre-bored pressuremeter test is characterized by minimal soil disturbance,strong adaptability,and intuitive results.It effectively avoids the disturbance caused by sampling and the differences in stress states between indoor and outdoor conditions.As a result,it is an effective means to reasonably understand the strength characteristics of reticulate silt clay.Taking an engineering project on the secondary terrace of Xiangjiang River as an example,the P-V curves of the reticular red soil at different depths were obtained through the pressuremeter tests of two drills,and its initial pressure,critical pressure and extreme pressure were obtained,and the corresponding mechanical parameters as modulus of pressuremeter,apparent deformation modulus and characteristic value of foundation bearing capacity were calculated.The pressuremeter curve,with three characteristic pressure values and two characteristic strength indicators,was correlated with indicators such as burial depth,characteristic value of soil bearing capacity,and compression modulus.It is found that the relevant mechanical parameters of the reticulate red soil do not gradually increase with the increase of depth,but are closely related to its states.By comparing and analyzing the load test results with those of the adjacent site,it was found that the characteristic value of the foundation bearing capacity obtained by pressuremeter test is close to the result of the load test and higher than the calculation value of the theoretical and the result of the standard penetration test.The results obtained in this paper can be used for reference in similar projects.

关 键 词：网纹红土 旁压试验 载荷试验 旁压模量 变形模量 承载力特征值 白沙井组 

分 类 号：TU446[建筑科学—岩土工程]