As a special and widely distributed geological material, the matrix-rock mixture (block-in-matrix texture) has been worldwide focused on its complex physical and mechanical properties for 25 years. However, the macro-meso mechanical relationship of matrix-rock mixture has not been well clarified so far, leading to the unclear understanding of its mechanical behavior. In this paper, the welded matrix-rock mixture is considered as a two-phase composite material, and a mesoscopic mechanical method is presented for calculating the uniaxial compressive strength (UCS). The influence of volumetric block proportion of rock (VBP) and mechanical contrast of meso components (i.e. UCS ratio (SR) and modulus ratio (MR) of rock to matrix) on the strength and the failure mechanism of the matrix-rock mixture is illustrated by the meso-inclusion theory. To avoid the rock damage in the welded mixture, it is suggested that the SR of rock to matrix should be larger than 1.5 for the low stiffness ratio of rock to matrix (e.g. MR ≤ 5), while for the mixture with high stiffness contrast (e.g. 5 < MR < 100) the SR of rock to matrix should be larger than 2. For the common case of strong rock-weak matrix mixture, the reinforced effect of VBP is positive with the MR of rock to matrix but seems to be insignificant when MR > 100. Meanwhile, the Weibull function is adopted to describe the strength property of the matrix in view of its strength randomness contributing to the matrix-rock mixture. It is shown that the strength evolution of the mixtures can be effectively predicted by the present model considering the Weibull distributed strength of the matrix, based on the comparison with the published experimental data and the discussion of existed empirical formulas.

作为一种特殊且分布广泛的地质材料，基质-岩石混合物（块状基质纹理）在全球范围内专注于其复杂的物理和机械特性已有25年了。然而，到目前为止，基岩混合体的宏观-介观力学关系尚未得到很好的阐明，导致对其力学行为的理解尚不清楚。本文将焊接的基岩混合物视为两相复合材料，并提出了介观力学方法来计算单轴抗压强度（UCS）。岩石的体积块比例（VBP）和细观分量的机械对比度（即UCS比（SR）和模量比（MR）细观夹杂理论说明了基岩混合体的强度和破坏机理。为了避免岩石对焊接混合物的破坏，建议对于较低的岩石与基质刚度比（例如MR≤5），而对于具有高刚度对比的混合物，岩石对基质的SR应该大于1.5。例如5 <  MR  <100），岩石对基体的SR应该大于2。对于强岩石-弱基体混合物的常见情况，VBP的增强效应与岩石对基体的MR是正的，但似乎微不足道当MR >100。同时，考虑到强度随机性对基岩混合物的影响，采用威布尔函数来描述基体的强度特性。结果表明，在与已发表的实验数据进行比较和对现有经验公式进行讨论的基础上，考虑基质的威布尔分布强度，本模型可以有效地预测混合物的强度演化。