【摘要】：目前巖石動態(tài)損傷本構模型未能很好地同時考慮臨界應變及已有損傷對被激活微裂紋數(shù)目的影響,為此,基于微裂紋在單軸壓縮荷載下的擴展機理,提出了新的巖石單軸壓縮動態(tài)損傷本構模型。在假定巖石中被激活的微裂紋數(shù)服從Weibull分布的基礎上,首先,通過臨界應變對被激活微裂紋數(shù)目的影響,建立了考慮臨界應變及微裂紋擴展長度的單軸壓縮損傷本構關系;其次,根據(jù)微裂紋在單軸壓縮下的翼裂紋擴展方程,考慮翼裂紋擴展過程中的慣性效應及翼裂紋擴展速度與應變率之間的關系,建立了單軸壓縮下巖石動態(tài)細觀損傷本構模型。最后采用數(shù)值算例對模型的合理性進行了驗證。結果表明:隨著Weibull分布參數(shù)k和m的增加,巖石動態(tài)抗壓峰值強度分布減小和增加,且m的影響更為顯著。隨著微裂紋摩擦系數(shù)、巖石斷裂韌性和應變率的增加,巖石動態(tài)抗壓峰值強度增加;而隨著微裂紋長度的增加,巖石動態(tài)峰值強度則降低。該結論與目前的研究成果較為一致,說明了該模型的合理性。
[Abstract]:At present, the dynamic damage constitutive model of rock fails to take into account both the critical strain and the effect of existing damage on the number of activated microcracks. Therefore, based on the propagation mechanism of microcracks under uniaxial compression load, A new dynamic damage constitutive model of rock under uniaxial compression is proposed. Based on the assumption that the number of activated microcracks in rock is distributed from Weibull, the uniaxial compression damage constitutive relation considering critical strain and microcrack propagation length is established through the influence of critical strain on the number of activated microcracks. Secondly, according to the wing crack propagation equation under uniaxial compression, considering the inertia effect during the crack growth and the relationship between the crack growth velocity and strain rate, the dynamic meso-damage constitutive model of rock under uniaxial compression is established. Finally, a numerical example is used to verify the rationality of the model. The results show that the peak strength distribution of rock dynamic compression decreases and increases with the increase of Weibull distribution parameters k and m, and the effect of m is more significant. With the increase of the friction coefficient of microcracks, the fracture toughness and strain rate of rock, the dynamic compressive peak strength of rock increases, while the dynamic peak strength of rock decreases with the increase of microcrack length. The conclusion is consistent with the current research results, which shows the rationality of the model.
【作者單位】： 黃淮學院建筑工程學院;中國地質大學(北京)工程技術學院;
【基金】：中央高校基本科研業(yè)務費專項資金項目(2652014019;2652015263) 國家自然科學基金項目(41162009)
【分類號】：TU45

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