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Outcome of meniscal repairs in paediatric population:A tertiary centre experience

World Journal of Orthopedics 2024年第6期15卷 547-553页

作者： Ayman Gabr Samson Williams Sophie Dodd nick barton-hanson Department of Trauma&Orthopaedics West Suffolk HospitalSuffolk IP332QZUnited Kingdom Department of Trauma and Orthopaedics Alder Hey Children's HospitalLiverpool L145ABUnited Kingdom

BACKGROUND Meniscal sparing surgery is a widely utilised treatment option for unstable meniscal tears with the aim of minimising the risk of progression towards ***,there is limited data in the literature on meniscal repair outcomes in skeletally immature *** To evaluate the re-operation rate and functional outcomes of meniscal repairs in children and *** We performed a retrospective review of all patients who underwent arthroscopic meniscal repair surgery between January 2007 and January *** patients were under the age of 18 at the time of *** were all performed by a single *** was gathered from our hospital Electronic Patient Records *** primary outcome measure was re-operation rate(need for further surgery on the same meniscus).Secondary outcome measures were surgical complications and patient reported outcome measures that were International Knee Documentation Committee(IKDC),Tegner and Lysholm *** We identified 59 patients who underwent 66 All-inside meniscal repairs(32 medial meniscus and 34 Lateral meniscus).Meniscal repairs were performed utilizing FasT-Fix(Smith and Nephew)*** were 37 males and 22 females with an average age of 14 years(range 6-16).The average follow-up time was 53 months(range 26-140).Six patients had concomitant anterior cruciate ligament reconstruction surgery along with the meniscal *** were no requiring further meniscal repairs and 9 patients underwent partial *** mean postoperative IKDC score was 88(44-100),Tegner score was 7(2-10)and Lysholm score was 94(57-100).CONCLUSION Our results showed that arthroscopic repair of meniscal tears in the paediatric population is an effective treatment option that has a low failure rate and good postoperative clinical with the advantage of preserving meniscal tissues.

关键词： Meniscus Meniscal repair Outcome Meniscal preservation

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A photogrammetric approach for quantifying the evolution of rock joint void geometry under varying contact states

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International Journal of Mining Science and Technology 2024年第4期34卷 461-477页

作者： Rui Yong Changshuo Wang nick barton Shigui Du Institute of Rock Mechanics Ningbo UniversityNingbo 315211China nick barton&Associates Fjordveien 65cHøvik 1363Norway

Accurate measurement of the evolution of rock joint void geometry is essential for comprehending the distribution characteristics of asperities responsible for shear and seepage ***,existing techniques often require specialized equipment and skilled operators,posing practical *** this study,a cost-effective photogrammetric approach is ***,local coordinate systems are established to facilitate the alignment and precise quantification of the relative position between two halves of a rock ***/pull tests are conducted on rock joints with varying roughness levels to induce different contact states.A high-precision laser scanner serves as a benchmark for evaluating the photogrammetry *** certain deviations exist,the measured evolution of void geometry is generally consistent with the qualitative findings of previous *** photogrammetric measurements yield comparable accuracy to laser scanning,with maximum errors of 13.2%for aperture and 14.4%for void *** joint matching coefficient(JMC)measurement errors are below 20%.Larger measurement errors occur primarily in highly mismatched rock joints with JMC values below 0.2,but even in cases where measurement errors exceed 80%,the maximum JMC error is only ***,the proposed photogrammetric approach holds promise for widespread application in void geometry measurements in rock joints.

关键词： Rock joint Void geometry evolution Photogrammetry Aperture Void volume Joint matching coefficient

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Advances in joint roughness coefficient (JRC) and its engineering applications

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第12期15卷 3352-3379页

作者： nick barton Changshuo Wang Rui Yong nick barton&Associates Fjordveien 65cHavik Oslo1363Norway School of Civil Engineeing Shijiazhuang Tiedao UniversityShijiazhuang050043China Rock Mechuanics Institute Ningbo UniversityNingbo315211China

The joint roughness coefficient (JRC), introduced in barton (1973) represented a new method in rock mechanics and rock engineering to deal with problems related to joint roughness and shear strength estimation. It has the advantages of its simple form, easy estimation, and explicit consideration of scale effects, which make it the most widely accepted parameter for roughness quantification since it was proposed. As a result, JRC has attracted the attention of many scholars who have developed JRC-related methods in many areas, such as geological engineering, multidisciplinary geosciences, mining mineral processing, civil engineering, environmental engineering, and water resources. Because of such a developing trend, an overview of JRC is presented here to provide a clear perspective on the concepts, methods, applications, and trends related to its extensions. This review mainly introduces the origin and connotation of JRC, JRC-related roughness measurement, JRC estimation methods, JRC-based roughness characteristics investigation, JRC-based rock joint property description, JRC's influence on rock mass properties, and JRC-based rock engineering applications. Moreover, the representativeness of the joint samples and the determination of the sampling interval for rock joint roughness measurements are discussed. In the future, the existing JRC-related methods will likely be further improved and extended in rock engineering.

关键词： Joint roughness coefficient(JRC) Rock joints Roughness Shear strength Scale effect

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Understanding the need for pre-injection from permeability measurements: What is the connection?

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第3期11卷 576-597页

作者： nick barton Eda Quadros nick barton & Associates OsloNorway BGTech Soil and Rock Engineering Ltd. Sao PauloBrazil

Pre-grouting ahead of tunnels has three main functions:to control water inflow into the tunnel,to limit groundwater drawdown above the tunnel,and to make tunnelling progress more predictable since rock mass quality is effectively *** helps to avoid settlement damage caused by consolidation of clay deposits beneath built-up areas,since towns tend to be built where terrain is more flat,due to the clay *** are so many instances of settlement damage that the profession needs to take note of the need for high-pressure pre-grouting,to use micro-cements and micro-silica *** use of highpressure injection may cause joint jacking,but this is local in extent when the rapid pressure decay away from an injection hole is *** effect is variable and depends on the geometrical parameters of the *** pressure-decay advantage must not be violated by maintaining high pressure when grout flow from the injection hole has *** latter can cause damage to the grouting already *** methods of estimating mean hydraulic apertures(e)from Lugeon testing are described,and from more sophisticated three-dimensional(3D)permeability *** estimation of the larger mean physical joint apertures(E)is based on the joint roughness coefficient(JRC).Comparison is then made with the empirical aperture-particle size criterion E>4d95,where d95 represents almost the largest cement particle *** on joint set orientations and on the available micro-cements,the decision must be made of which range of pre-injection pressure should be aimed for,using successive reductions of the water-cement ratio w/*** simple estimation of permeability,also with depth dependence,can be made with the empirical link between a modified rock mass quality Q and permeability,which is termed *** value of this parameter can be based on core-logging or intunnel face *** 3D before-and-after-grouting permeability measurements have been use

关键词： Pre-grouting Micro-cement Hydraulic apertures Physical joint apertures Joint roughness Particle size Anisotropic permeability

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Risk of shear failure and extensional failure around over-stressed excavations in brittle rock

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第2期9卷 210-225页

作者： nick barton Baotang Shen nick barton&Associates OsloNorway CSIRO Energy BrisbaneAustralia

The authors investigate the failure modes surrounding over-stressed tunnels in *** lines of investigation are employed:failure in over-stressed three-dimensional(3D) models of tunnels bored under 3D stress,failure modes in two-dimensional(2D) numerical simulations of 1000 m and 2000 m deep tunnels using FRACOD,both in intact rock and in rock masses with one or two joint sets,and finally,observations in TBM(tunnel boring machine) tunnels in hard and medium hard massive *** reason for 'stress-induced' failure to initiate,when the assumed maximum tangential stress is approximately(0.4-0.5)σ_c(UCS,uniaxial compressive strength) in massive rock,is now known to be due to exceedance of a critical extensional strain which is generated by a Poisson's ratio ***,because similar 'stress/strength' failure limits are found in mining,nuclear waste research excavations,and deep road tunnels in Norway,one is easily misled into thinking of compressive stress induced *** of this,the empirical SRF(stress reduction factor in the Q-system) is set to accelerate as the estimated ratio σ_(θmax)/σ_c >> *** mining,similar 'stress/strength' ratios are used to suggest depth of *** reality behind the fracture initiation stress/strength ratio of '0.4' is actually because of combinations of familiar tensile and compressive strength ratios(such as 10) with Poisson's ratio(say0.25).We exceed the extensional strain limits and start to see acoustic emission(AE) when tangential stress σθ ≈ 0.4σc,due to simple *** combination of 2D theoretical FRACOD models and actual tunnelling suggests frequent initiation of failure by 'stable' extensional strain fracturing,but propagation in 'unstable' and therefore dynamic *** the case of very deep tunnels(and 3D physical simulations),compressive stresses may be too high for extensional strain fracturing,and shearing will dominate,both ahead of the face and following the *** shallower,the conc

关键词： Fracture propagation Tension Shear Poisson’s ratio Break-out Rock burst Deep tunnels FRACOD model

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Shear strength criteria for rock,rock joints,rockfill and rock masses:Problems and some solutions

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Journal of Rock Mechanics and Geotechnical Engineering 2013年第4期5卷 249-261页

作者： nick barton nick barton & Associates OsloNorway

Although many intact rock types can be very strong,a critical confining pressure can eventually be reached in triaxial testing,such that the Mohr shear strength envelope becomes *** critical state has recently been better defined,and correct curvature or correct deviation from linear Mohr-Coulomb（MC） has finally been *** shear testing procedures for rock joints,using multiple testing of the same sample,in case of insufficient samples,can be shown to exaggerate apparent *** rough joints do not have any cohesion,but instead have very high friction angles at low stress,due to strong *** masses,implying problems of large-scale interaction with engineering structures,may have both cohesive and frictional strength ***,it is not correct to add these,following linear M-C or nonlinear Hoek-Brown（H-B） standard *** is broken at small strain,while friction is mobilized at larger strain and remains to the end of the shear *** criterion ＇c then σn tan φ＇ should replace ＇c plus σn tan φ＇ for improved fit to *** of principal stresses to a shear plane seems to ignore mobilized dilation,and caused great experimental difficulties until *** seems to be plenty of room for continued research,so that errors of judgement of the last 50 years can be corrected.

关键词： Rock masses Critical state Rock joints Shear strength Non-linear friction Cohesion Dilation Scale effects Numerical modelling Stress transforms

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An approximate nonlinear modified Mohr-Coulomb shear strength criterion with critical state for intact rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第4期10卷 645-652页

作者： Baotang Shen Jingyu Shi nick barton State Key Laboratory of Mining Disaster Prevention and Control Shandong University of Science and TechnologyQingdaoChina CSIRO Energy QCAT1 Technology CourtPullenvaleQLD4069Australia nick barton&Associates OsloNorway

In this paper, the Mohr-Coulomb shear strength criterion is modified by mobilising the cohesion and internal friction angle with normal stress, in order to capture the nonlinearity and critical state concept for intact rocks reported in the literature. The mathematical expression for the strength is the same as the classical form, but the terms of cohesion and internal friction angle depend on the normal stress now,leading to a nonlinear relationship between the strength and normal stress. It covers both the tension and compression regions with different expressions for cohesion and internal friction angle. The strengths from the two regions join continuously at the transition of zero normal stress. The part in the compression region approximately satisfies the conditions of critical state, where the maximum shear strength is reached. Due to the nonlinearity, the classical simple relationship between the parameters of cohesion, internal friction angle and uniaxial compressive strength from the linear Mohr-Coulomb criterion does not hold anymore. The equation for determining one of the three parameters in terms of the other two is supplied. This equation is nonlinear and thus a nonlinear equation solver is needed. For simplicity, the classical linear relationship is used as a local approximation. The approximate modified Mohr-Coulomb criterion has been implemented in a fracture mechanics based numerical code FRACOD,and an example case of deep tunnel failure is presented to demonstrate the difference between the original and modified Mohr-Coulomb criteria. It is shown that the nonlinear modified Mohr-Coulomb criterion predicts somewhat deeper and more intensive fracturing regions in the surrounding rock mass than the original linear Mohr-Coulomb criterion. A more comprehensive piecewise nonlinear shear strength criterion is also included in Appendix B for those readers who are interested. It covers the tensile, compressive, brittle-ductile behaviour transition and the

关键词： Shear strength Modified Mohr-Coulomb criterion Critical state Intact rock

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Nonlinear shear behavior of rock joints using a linearized implementation of the barton-Bandis model

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第4期9卷 671-682页

作者： Simon Heru Prassetyo Marte Gutierrez nick barton Department of Civil and Environmental Engineering Colorado School of Mines Golden CO 80401 USA nick barton and Associates Oslo Norway

Experiments on rock joint behaviors have shown that joint surface roughness is mobilized under shearing,inducing dilation and resulting in nonlinear joint shear strength and shear stress *** displacement *** barton-Bandis(B-B) joint model provides the most realistic prediction for the nonlinear shear behavior of rock *** B-B model accounts for asperity roughness and strength through the joint roughness coefficient(JRC) and joint wall compressive strength(JCS) ***,many computer codes for rock engineering analysis still use the constant shear strength parameters from the linear Mohr-Coulomb(M-C) model,which is only appropriate for smooth and non-dilatant *** limitation prevents fractured rock models from capturing the nonlinearity of joint shear *** bridge the B-B and the M C models,this paper aims to provide a linearized implementation of the B-B model using a tangential technique to obtain the equivalent M-C parameters that can satisfy the nonlinear shear behavior of rock *** equivalent parameters,namely the equivalent peak cohesion,friction angle,and dilation angle,are then converted into their mobilized forms to account for the mobilization and degradation of JRC under *** conversion is done by expressing JRC in the equivalent peak parameters as functions of joint shear displacement using proposed hyperbolic and logarithmic functions at the pre-and post-peak regions of shear displacement,***,the pre-and post-peak joint shear stiffnesses are derived so that a complete shear stress-shear displacement relationship can be *** of the linearized implementation of the B-B model show that the shear stress-shear displacement curves,the dilation behavior,and the shear strength envelopes of rock joints are consistent with available experimental and numerical results.

关键词： Rock joints Joint shear behavior Friction and dilation barton-Bandis(B-B) model Equivalent Mohr-Coulomb(M-C) parameters

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Reducing risk in long deep tunnels by using TBM and drill-and-blast methods in the same project-the hybrid solution

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Journal of Rock Mechanics and Geotechnical Engineering 2012年第2期4卷 115-126页

作者： nick barton NB&A

There are many examples of TBM tunnels through mountains, or in mountainous terrain, which have suffered the ultimate fate of abandonment, due to insufficient pre-investigation. Depth-of-drilling limitations are inevitable when depths approach or even exceed l or 2 km. Uncertainties about the geology, hydro-geology, rock stresses and rock strengths go hand-in-hand with deep or ultra-deep tunnels. Unfortunately, unexpected conditions tend to have a much bigger impact on TBM projects than on drill-and-blast projects. There are two obvious reasons. Firstly the circular excavation maximizes the tangential stress, making the relation to rock strength a higher source of potential risk. Secondly, the TBM may have been progressing fast enough to make probe-drilling seem to be unnecessary. If the stress-to-strength ratio becomes too high, or if faulted rock with high water pressure is unexpectedly encountered, the ＂unexpected events＂ may have a remarkable delaying effect on TBM. A simple equation explains this phenomenon, via the adverse local Q-value that links directly to utilization. One may witness dramatic reductions in utilization, meaning ultra-steep deceleration-of-the-TBM gradients in a log-log plot of advance rate versus time. Some delays can be avoided or reduced with new TBM designs, where belief in the need for probe-drilling and sometimes also pre-injection, have been fully appreciated. Drill-and-blast tunneling, inevitably involving numerous ＂probe-holes＂ prior to each advance, should be used instead, if investigations have been too limited. TBM should be used where there is lower cover and where more is known about the rock and structural conditions. The advantages of the superior speed of TBM may then be fully realized. Choosing TBM because a tunnel is very long increases risk due to the law of deceleration with increased length, especially if there is limited pre-investigation because of tunnel depth.

关键词： tunnel boring machine (TBM) rock strength deep tunnels tangential stress pre-injection Q-values utilization risk

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岩石、节理以及岩体抗剪强度的相关问题与解决方法

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地壳构造与地壳应力 2014年第2期 1-28页

作者： N.R. barton 江英豪 nick barton &Associates

岩石、节理以及岩体抗剪强度这三个重要的论题,每个论题即使是概括性的讨论,也都值得使用单独的论卷来深入讨论,但本文仅在一篇文章中将它们联系起来进行总结。包罗万象的岩体剪切强度既不能用Hoek-Brown准则中的高级代数来表述,也无法... 详细信息

岩石、节理以及岩体抗剪强度这三个重要的论题,每个论题即使是概括性的讨论,也都值得使用单独的论卷来深入讨论,但本文仅在一篇文章中将它们联系起来进行总结。包罗万象的岩体剪切强度既不能用Hoek-Brown准则中的高级代数来表述,也无法用摩尔-库仑的线性准则来定义,因为这些方法都是预先估计,而不是建立在经验上的后续检验。完整岩体的高度非线性的剪切强度是小应变破坏时的重要组成部分,其定义严重偏离了摩尔库伦准则所定义的曲线,而且曲率也比Hoek-Brown准则所定义的曲线大。在地壳岩石的深处或许是塑性的,或者处于它们的临界状态。这些不同的脆弱的节理和裂缝,给土木和采矿工程的稳定性方面制造了诸多难题,但是它们也是帮助裂隙化储层维持渗透性的重要因素。节理具备高度各向异性的特点。节理裂隙在高法向刚度和低尺度的剪切刚度条件下呈现出的属性特征差异非常大。正如1966年穆勒在书中所述,与完整的岩体相比,节理能够在更大的剪切应变下明显地达到最大剪切强度,而且在内聚力消失后,仍然保持它们的摩擦力。在非线性Hoek-Brown表达式中和内聚力c加上?tan的条件下,增加完整岩体的内聚力以及节理的剪切阻力是错误的。在更大的剪切应变下存在第三个剪切强度分量,在粘土填充的(比如在断层附近的区域)的不连续区域存在更小的摩擦力强度。最后,这里存在某一平面上的从主应力、到正应力再到剪切应力的应力转换大问题。侧向膨胀、剪切破坏以及该平面的存在都违背了原始的理论假设。

关键词：节理裂隙完整岩体抗剪强度地壳岩石剪切强度 Brown 剪切应变不连续区域

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