深部黏土的土力学内涵及关键试验技术初探

深部黏土地层是深部岩土工程中的常见土层,然而目前对其力学性质的认识尚落后于工程实践。首先通过与浅部硬黏土、浅部非硬质黏土等工程概念的对比分析,表明深部黏土具有独特的土力学内涵,即处于高压工况的饱和正常高压固结硬黏土,同时指出了无论是非硬质正常固结黏土或者是硬质的严重超固结黏土,其相关理论并不适合于少量已获得的正常高压固结硬黏土的力学性质;其次介绍了系统开展正常高压固结黏土力学试验的技术瓶颈在于高压固结阶段的严重耗时特点,分析了将高压固结阶段与后续剪切阶段分开进行的必要性;最后介绍了用于批量制备高压固结黏土试样的大尺寸高压固结试验系统的研制与初步应用实例。

Soil Mechanics Implication of Deep Clay and a Preliminary Study on Its Key Experimental Technology

Deep clay strata is usually met in deep geotechnical engineering. However, the knowledge of its mechanical properties lags behind the engineering practice. Firstly, through the comparative analysis of the engineering concepts including shallow stiff clay and shallow non-stiff clay, it found that deep clay had unique soil mechanics implication which was the normally high-pressure consolidated saturated clay working under high pressure. Additional, it was indicated that the theories obtained from the tests of both of normally consolidated non-stiff clay and heavily over-consolidated stiff clay seemed not apply to a few observed mechanical behavior of normally consolidated stiff clay. Secondly, it was introduced that the technical bottleneck in the systematic experimental study on the normally high-pressure consolidated clay was that the high-pressure consolidation of clay was very time consuming, and it was indicated that the separation of high-pressure consolidation stage and the following shearing stage was necessary. In the last, a large size high-pressure oedometer was developed for the batch preparation of high-pressure consolidated specimens and its preliminary application were introduced.