为探明采用点荷载对机制砂用隧道洞渣饱和抗压强度进行快速评价的可行性,以点荷载强度指数为评价指标,研究加载方式、含水状态对20种不同岩性隧道洞渣点荷载强度指数的影响规律,建立隧道洞渣点荷载强度指数与饱和抗压强度的关系。结果表明: 1)隧道洞渣点荷载强度指数与其饱和抗压强度具有较高的相关性,依据变质岩、沉积岩及岩浆岩等不同岩性分类得到的关系式相关性更高; 2)当轴向点荷载强度指数超过8.0 MPa时,不同加载方式下的隧道洞渣点荷载强度指数存在差异,径向加载与轴向加载的点荷载强度指数相近,不规则块体加载与轴向加载的点荷载强度指数差值增大; 3)隧道洞渣点荷载强度损失率与其含水率具有线性相关性,含水率越高,点荷载强度损失率越大。基于此,提出不同含水状态下的隧道洞渣饱和抗压强度预测公式。
Herein, the feasibility of using a point load for
rapid evaluation of the saturated compressive strength(SCS) of tunnel muck is
assessed by analyzing the effect of the loading mode and hydrous state of
tunnel muck on the point load strength index(PLSI) of 20 tunnel muck samples
with various lithologies. A correlation analysis is performed on the PLSI and
SCS of the tunnel muck. The following results are obtained: (1) The PLSI is
highly correlated with the SCS for samples with different lithologies,
including metamorphic, sedimentary, and igneous rocks. (2) When the axial PLSI
is >8.0 MPa, the PLSIs measured under different loading modes vary; the PLSIs
measured under radial and axial loading are similar. However, the difference in
the PLSIs measured under irregular and axial loading increases with the point
load. The loss rate of the PLSI is positively and linearly correlated with the
water content of the tunnel muck. The aforementioned results are used to
propose prediction formulas for tunnel muck SCS in different hydrous states.