Approximate Theoretical Analysis on Excavation Disturbed Zone of a Soft Rock Slope in Suining-Ziyang Expressway Engineering in Southwestern China

A cutting slope model can be simplified as plane strain one, the stress field of cutting slope can be analyzed with elastic wedge body theory. By using strength criterion of slope material (Mohr-Coulomb strength criterion with safety reserve and uniaxial tensile strength criterion), the disturbed zone caused by excavation can be calculated in 3D stress state, so all the disturbed zone after each step of excavation from the top down can be searched out. The main analysis steps for judging disturbed zone are described in the paper, including the methods to calculate the stress state of cutting slope, the unloading value and the scope of disturbed zone after last step of excavation. Finally, an example in Suining-Ziyang expressway engineering is chosen to explain detailedly the analytical process with elastic wedge body theory to determine the disturbed zone.

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Strength Assessment of Broken Rock Postgrouting Reinforcement Based on Initial Broken Rock Quality and Grouting Quality

Mathematical Problems in Engineering ◽

10.1155/2017/3651765 ◽

2017 ◽

Vol 2017 ◽

pp. 1-14 ◽

Cited By ~ 4

Author(s):

Hongfa Xu ◽

Hansheng Geng ◽

Feng Chen ◽

Xiao Chen ◽

Liangliang Qi

Keyword(s):

Rock Mass ◽

Internal Friction ◽

Growth Rates ◽

Strength Criterion ◽

Friction Angle ◽

Uniaxial Tensile ◽

Strength Assessment ◽

Uniaxial Tensile Strength ◽

Quantitative Calculation ◽

Grouting Reinforcement

To estimate postgrouting rock mass strength growth is important for engineering design. In this paper, using self-developed indoor pressure-grouting devices, 19 groups of test cubic blocks were made of the different water cement ratio grouting into the broken rock of three kinds of particle sizes. The shear strength parameters of each group under different conditions were tested. Then this paper presents a quantitative calculation method for predicting the strength growth of grouted broken rock. Relational equations were developed to investigate the relationship between the growth rates of uniaxial compressive strength (UCS), absolute value of uniaxial tensile strength (AUTS), internal friction angle, and cohesion for post- to pregrouting broken rock based on Mohr-Coulomb strength criterion. From previous test data, the empirical equation between the growth rate of UCS and the ratio of the initial rock mass UCS to the grout concretion UCS has been determined. The equations of the growth rates of the internal friction coefficient and UCS for grouting broken rock with rock mass rating (RMR) and its increment have been established. The calculated results are consistent with the experimental results. These observations are important for engineered design of grouting reinforcement for broken rock mass.

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Two-Parameter Parabolic Mohr Strength Criterion Applied to Analyze the Results of the Brazilian Test

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.624.630 ◽

2014 ◽

Vol 624 ◽

pp. 630-634 ◽

Cited By ~ 1

Author(s):

Qi Fan ◽

Shuan Cheng Gu ◽

Bo Nan Wang ◽

Rong Bin Huang

Keyword(s):

Tensile Strength ◽

Stress State ◽

Tensile Stress ◽

Failure Modes ◽

Strength Criterion ◽

Complex Stress State ◽

Brazilian Test ◽

Practical Significance ◽

Uniaxial Tensile ◽

Two Parameter

Geotechnical engineering in tension damage is one of the major failure modes. For a long time, Brazil test has practical significance and wide application value that has been used to determine the tensile strength of rock. When the specimen center destroyed tensile stress play a major role that is the theoretical basis of Brazil test. This is uniaxial tensile stress state, but the reality is complex stress state. Theoretical analysis shows that the Brazilian test does not truly reflect the tensile strength of rock, its test results to error. In this paper, two-parameter parabolic Mohr strength criterion for this error analysis, and propose amendments to the formula.

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