饱和重塑黏土空心圆柱试样的压制技术及应用
Compression method for hollow cylinder specimens of saturated remolded clay and its application
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摘要: 由于黏土黏性大、受扰动易产生裂隙,采用常规的击实法和固结法所制备的空心圆柱试样存在整体不均匀、饱和度较低、切削面裂隙丰富等问题。在重塑试样击实器的基础上,研制了一种能制备实心与空心圆柱重塑试样的压样装置,可以很好地模拟天然状态下土体形成过程。依据改进的分层欠压法,试验选取最优初始欠压系数,在每层试样高度相同的条件下,严格控制每层试样的质量,而后采用抽气饱和法将所压制的试样进行饱和。通过应力路径三轴试验和纯主应力轴旋转试验,从可重复性和力学特性两个方面验证了所制备的饱和重塑黏土试样用于研究复杂应力路径下土体变形特性与本构关系的可靠性,为后续重塑土的理论与试验研究提供了重要的保证。Abstract: Due to the viscosity and easy-cracked characteristics of clay, series problems, such as non-homogeneity, low-saturation and microcracks, exist in the hollow cylinder specimens generally made by using the compaction method and the consolidation method. Based on the traditional compacting instrument, a newly designed specimen presser can be employed to prepare the remolded solid and hollow cylindrical specimens by simulating the forming process of natural soils. According to the improved undercompaction method and the optimal initial undercompaction coefficient obtained by tests, the quality of each layer is controlled strictly with the same height. After being saturated by the pumping saturation method, the reliability of remolded specimens is proved considering the repeatability and mechanical properties when the specimens are used to study the deformation characteristics and the constitutive relation of soils under complex stress paths. All those may provide the assurance of long-term studies on saturated remolded clay.