静力触探在海底土层工程性质评价中的应用研究

随着海底隧道建设、海岸带开发、港湾建设和其他海洋资源的开发,静力触探技术(CPT)作为原位测试技术的一种,在海洋工程地质勘查中发挥着越来越重要的作用。现场进行静力触探试验以及室内试验,分析某海上场址工程中土的物理、力学性质的特点,通过对比分析对土层的抗剪强度、灵敏度和超固结比(OCR)进行评价。CPT测试数据显示当地层发生变化时,锥尖阻力(qc)和孔隙水压力(fs)会发生较大变化。对于较硬的黏土层,静力触探结果可能出现较大误差,土性参数评价时需要予以剔除。使用CPT测试数据对该场址地基土不排水抗剪强度、灵敏度和超固结比(OCR)进行评价时,其各自参数分别为:Nkt取15,Ns取6以及k值取0.3时,CPT测得不排水抗剪强度、灵敏度和超固结比与室内试验吻合较好。

The Application of Cone Penetration Test in Subsea Soil Geotechnical Properties Evaluation

With the development of the subsea tunnel, coastal zone, harbor construction, and other marine resources development, especially for the offshore marine engineering, the cone penetration test (CPT) technology plays an increasingly important role in the offshore engineering geological survey. The physical and mechanical properties of soils in an offshore platform were analyzed by the site cone penetration test and laboratory test. Based on the comparion studies of these two methods, the shear strength, sensitivity, and over consolidation ratio of the offshore soil were evaluated. The CPT results show that tip resistance (q_c) and pore water pressure (f_s) changed greatly with the local layer changes. For hard clay layer, the CPT results may appear large error. Therefore, the soil parameters of the hard clay layers should be removed. During the evaluation, when the paramaters of N_kt, N_s, and k equal to 15, 6 and 0.3, respectively, the shear strength, sensitivity, and over consolidation ratio (OCR) values from the CPT could match the results from the laboratury tests.