重塑黏土空心圆柱试样制备技术改进及应用

Improvement of preparing technique for hollow cylinder specimen of remolded clay and its application

受大体积制样降低土体均衡性及取芯扰动试样的影响,目前在包括主应力轴旋转等复杂应力路径下所开展的重塑软黏土力学特性试验研究的可靠性有待进一步提高。基于真空预压技术设计了制备重塑样的新型装置及方法,具有渗透排水与内壁成型双重作用的竖向排水体、分级施加真空负压以及多个试样同时制作等部件和技术,可快速制备大量空心圆柱试样,所制试样含水率具有较好的均匀性和一致性,减小了后期取芯对试样造成的扰动。开展了主应力轴旋转路径下的相关验证试验,从土体力学性能方面证明了所制试样用于研究复杂应力路径条件下土体性态演变规律的可靠性,为系统研究软黏土静动力学特性与长期稳定性提供了前提。

Under complex stress path including principal stress rotation, the research on remolded soft clay mechanical characteristics needs to improve its reliability, because the large volume's method of specimen preparation reduces the physical balance and coring operation disturbances the sample. Based on vacuum preloading technology, a new kind of device and method is designed to prepare remolded specimen. The core component is the vertical drain body, which has a dual role of drainage and the inner wall molding. The important technology includes gradation loading of vacuum preloading and simultaneously preparing multiple samples. The method can prepare multiple hollow cylinder specimens quickly; the specimen's moisture is better uniformity and consistency. This method can reduce the disturbance of the specimen of late coring operation. The verification tests is carried out under principal stress rotation path. The specimen's reliability is proved, considering aspects of soil mechanical characteristics, when the specimen is applied to studying the of soil behavior evolution law under complex stress path. The specimen also provides the prerequisite for the static and dynamic mechanical characteristics systematic study and long-term stability of soft clay.