余玮平,顾琳琳,王振,等. 2021. 钙质砂颗粒破碎对临界状态影响的试验研究[J]. 工程地质学报,29(5):1276-1285. doi: 10.13544/j.cnki.jeg.2021-0477.
    引用本文: 余玮平,顾琳琳,王振,等. 2021. 钙质砂颗粒破碎对临界状态影响的试验研究[J]. 工程地质学报,29(5):1276-1285. doi: 10.13544/j.cnki.jeg.2021-0477.
    Yu Weiping, Gu Linlin, Wang Zhen, et al. 2021. Experimental study on influence of particle breakage to critical state of calcareous sand[J]. Journal of Engineering Geology, 29(5): 1276-1285. doi: 10.13544/j.cnki.jeg.2021-0477.
    Citation: Yu Weiping, Gu Linlin, Wang Zhen, et al. 2021. Experimental study on influence of particle breakage to critical state of calcareous sand[J]. Journal of Engineering Geology, 29(5): 1276-1285. doi: 10.13544/j.cnki.jeg.2021-0477.

    钙质砂颗粒破碎对临界状态影响的试验研究

    EXPERIMENTAL STUDY ON INFLUENCE OF PARTICLE BREAKAGE TO CRITICAL STATE OF CALCAREOUS SAND

    • 摘要: 钙质砂的颗粒易碎性是造成其变形和强度特性不同于石英砂的重要性质。本文基于临界状态理论,通过一系列试验定量地描述钙质砂临界状态线随颗粒破碎的演化规律。本文试验分两个阶段进行:第1阶段研究了60~2000 kPa围压条件下钙质砂的力学特性和颗粒破碎特征;第2阶段以不同破碎率的试样为母本重塑制样,在100~300 kPa围压条件下,剪切至破碎临界状态线。试验结果表明:在较小围压(<300 kPa)条件下,松砂和密砂均表现出明显的剪胀和应变软化特性;而高围压(>1 MPa)条件下,显著的颗粒破碎会造成试样的持续剪缩;颗粒破碎存在明显围压阈值,对于松砂而言,在围压小于300 kPa条件下,颗粒基本不发生破碎;在e-lg p'平面内,破碎临界状态线的截距ΔeΓ和斜率λc均会随着修正相对破碎率Br*的增大而减小,即颗粒破碎会使临界状态线发生下移和逆时针转动;而在q-p'平面内,钙质砂的临界状态点落在同一条直线上,即存在唯一的临界状态应力比Mcr和临界摩擦角φcr

       

      Abstract: The particle fragility of calcareous sand is an important property that causes its deformation and strength characteristics different from standard sand. Based on the critical state theory,this paper quantitatively reveals the evolution of the critical state line of calcareous sand with particle breakage through a series of experiments. The experiment is carried out in two different stages. In the first stage,the deformation characteristics and particle breakage characteristics of calcareous sand under different confining pressures(60~2000 kPa) are analyzed. In the second stage,the samples with different crushing rates produced from the first stage is reshaped,he second shearing under the confining pressure of 100~300 kPa is performed,then the crushing critical state line is acquired. The test results show that under low confining pressure(<300 kPa) both loose and dense sand show the strain softening and dilatancy characteristics. While under high confining pressure(>1 MPa),significant particle breakage causes continuous shear contraction. There is an obvious confining pressure threshold for particle breakage. For loose sand,there is basically no particle breakage when the confining pressure is less than 300 kPa. In the e-lg p' plane,the intercept ΔeΓ and the slope λc of the crushing critical state line decreases with the increase of Br*,so the particle breakage makes the critical state line move downward and rotate counterclockwise. While in the q-p' plane,the critical state points of calcareous sand fall on the same straight line,indicating that there is a unique critical state stress ratio Mcr and critical friction angle φcr.

       

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