In response to the complex mechanical characteristics of sandy dolomite in the Central Yunnan Water Diversion (CYWD) Project, this study constructs a multi-parameter strength prediction model (the power function relationship between UCS and SH, Is(50), Vp, ρ, n, with an R2 value ranging from 0.593 to 0.973) through in-situ tests (Schmidt rebound, point load, wave velocity test) and laboratory tests (uniaxial compressive strength and triaxial compression). It also proposes a three-dimensional constitutive model parameter calibration method based on the Generalized Zhang-Zhu (GZZ) criterion. True triaxial tests demonstrate that the intermediate principal stress (σ2) exerts a significant influence on the brittle-ductile transition and strength properties of sandy dolomite, as evidenced by a 133% increase in peak strength of σ1 at σ2 = 0.8 σ1. By calibrating parameters (GSI = 84.57, a = 0.5, s = 0.4285), the theoretical yield surface predicted by the GZZ criterion shows a high degree of agreement with the experimental data (average error < 5%), thereby confirming its applicability in a three-dimensional stress field. The parameter sensitivity analysis indicates that a has a significant effect on the yield surface morphology (the yield surface is expanded twofold when a = 0.8), while s only causes the overall translation. Engineering case studies further indicate that optimized parameters (a = 0.7, s = 0.45) effectively reduce the extent of the plastic region in surrounding rock by 23%, providing a robust tool for engineering stability analysis of deep sandified rock mass engineering.Highlights<UnorderedList Mark="Bullet"> <ItemContent> Intermediate stress σ2 increases peak strength by up to 133% and mitigates brittle failure. </ItemContent> <ItemContent> The multi-parameter model establishes a strong correlation between UCS and parameters such as SH, Is(50), and Vp, with an R2 value reaching as high as 0.973. </ItemContent> <ItemContent> Calibrated GZZ criterion demonstrates < 5% error and reduces the plastic region by 23% with optimized parameters. </ItemContent> <ItemContent> Validated in deep tunnel excavation significantly enhances stability analysis for sandy dolomite engineering. </ItemContent> </UnorderedList>

Three-Dimensional Nonlinear GZZ Strength Criterion of Sandy Dolomite: Verification by True Triaxis Test and Analysis of Intermediate Principal Stress Effect

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发表日期：

2025年11月11日

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Qifu Xu,
Wei Xu,
Guangcai Qian,
Meiqian Wang

摘要

In response to the complex mechanical characteristics of sandy dolomite in the Central Yunnan Water Diversion (CYWD) Project, this study constructs a multi-parameter strength prediction model (the power function relationship between UCS and SH, I_s(50), Vp, ρ, n, with an R² value ranging from 0.593 to 0.973) through in-situ tests (Schmidt rebound, point load, wave velocity test) and laboratory tests (uniaxial compressive strength and triaxial compression). It also proposes a three-dimensional constitutive model parameter calibration method based on the Generalized Zhang-Zhu (GZZ) criterion. True triaxial tests demonstrate that the intermediate principal stress (σ₂) exerts a significant influence on the brittle-ductile transition and strength properties of sandy dolomite, as evidenced by a 133% increase in peak strength of σ₁ at σ₂ = 0.8 σ₁. By calibrating parameters (GSI = 84.57, a = 0.5, s = 0.4285), the theoretical yield surface predicted by the GZZ criterion shows a high degree of agreement with the experimental data (average error < 5%), thereby confirming its applicability in a three-dimensional stress field. The parameter sensitivity analysis indicates that a has a significant effect on the yield surface morphology (the yield surface is expanded twofold when a = 0.8), while s only causes the overall translation. Engineering case studies further indicate that optimized parameters (a = 0.7, s = 0.45) effectively reduce the extent of the plastic region in surrounding rock by 23%, providing a robust tool for engineering stability analysis of deep sandified rock mass engineering.

Highlights

Intermediate stress σ₂ increases peak strength by up to 133% and mitigates brittle failure.

The multi-parameter model establishes a strong correlation between UCS and parameters such as SH, I_s(50), and V_p, with an R² value reaching as high as 0.973.

Calibrated GZZ criterion demonstrates < 5% error and reduces the plastic region by 23% with optimized parameters.

Validated in deep tunnel excavation significantly enhances stability analysis for sandy dolomite engineering.