第二类： AB

The figure shows that as the grout stiffness decreases, the number of modes determined with the exponential solution in the fixed length also decreases.
Unit 6
Presentation
完成人：郝 阳 TB16220005B2 杨胜利 DB16220017B8
2016.10
第一篇：

Title：Non-destructive testing of rock bolts using guided ultrasonic waves
Author：Beard, M. D.; Lowe, M. J. S Addresses：Univ London Imperial Coll Sci Technol & Med, Dept Mech Engn, London SW7 2BX, England Journal information: International Journal of Rock Mechanics and Mining Sciences, 2003. 40(4): p. 527-536. Impact Factor:

第二篇：

Title：Non-destructive testing of rock bolts for estimating total bolt length Author：Ivanović, A. and R.D. Neilson, Addresses：Univ Aberdeen, Kings Coll, Coll Phys Sci, Sch Engn, Fraser Noble Bldg, Aberdeen AB24 3UE, Scotland.




第一类：AB

The drier the wood, the better its strength properties were, since plastic behaviour was reached with fewer deformations, but at higher pressures.(第三类和第一类同时存在） As the horizontal stresses increase (Ko), the value of the maximum subsidence decreases and the stress state of the ground ahead of the coalface increases.（第三类和第一类同时存在）

第一类：AB

the higher the stiffness of the grout along the fixed length, the more exponential solutions are obtained for a given length ratio The higher length ratios result in more exponential modes. the higher stiffness ratio of k^ ¼ 500, reveals a higher amplitude in the fixed length compared to the free length. This again suggests that a device capable of exciting higher frequencies would give more information on the condition of the rock bolt


Journal information: International Journal of Rock Mechanics and Mining Sciences, 2013. 64: p. 36-43.
Impact Factor:

第一类：AB

The findings from a parametric study undertaken previously by the authors indicate that with an increase of the Young’s modulus of the grout or a decrease of the borehole the shear stiffness of the grout annulus is greater （一个句子同时使用了 第一类和第四类）

第四类：AB

The thickness decreases as the distance from the coalface to the fault increases.
第四篇：


Title：Analytical models for rock bolts
Author：Li, C.; Stillborg, B Addresses：Division of Rock Mechanics, LuleaÊ University of Technology, SE-971 87 LuleaÊ , Sweden
第二类：AB

无
第三类：AB

Fiin epoxy modulus shifts the attenuation minimum both to a lower value and a lower frequency. This is because lowering the epoxy modulus increases the contrast of acoustic impedance at both the epoxy/bolt and epoxy/rock boundaries, and the wave is less well coupled to the rock.（同时存在第三类和第四类）

第二类：AB

无
第三类：AB

As the horizontal stresses increase (Ko), the value of the maximum subsidence decreases and the stress state of the ground ahead of the coalface increases.（第一类和第三类同时存在） To avoid this lateral confinement, the distance db was increased to 2.5 m in model M5, thus distancing the border of the model and the following line of props and notably reducing the lateral confinement.
This in turn results in an increase in natural frequency with increasing load. Fig. 10 shows an example of the rise in first natural frequency (an exponential mode) associated with the increase of head stiffness, which generally occurs for increasing load in the rock bolt
第三类：AB

For both the sinusoidal and exponential solutions there is a trend of increasing frequency ratio as the length ratio decreases although for the exponential solution this is more apparent than for the sinusoidal solution.
第三篇：

Title：Analysis of support by hydraulic props in a longwall working
Author：C. González-Nicieza; A. Menéndez-Dí az; A.E. Álvarez-Vigil; M.I. Álvarez-Fernández Addresses：Department of Mining Engineering, Mining Engineering School, University of Oviedo, Independencia 13, 33004, Asturias, Spain Journal information: International Journal of Coal Geology, 2008. 74(4): p. 527-536. Impact Factor:
第二类：AB

无
第三类：AB

Rock bolts in situ tend to restrain the deformation of rock with an increase in their axial loads.
第四类：AB

When the applied load is small, the shear stress decreases with increasing distance from the point of loading . When the opening displacement of the joint is small, both the shear stress and the axial stress decrease exponentially with increasing distance from the joint. The shear stress on the non-decoupled interface decreases exponentially with increasing distance from the decoupling front.