以川西某隧道开挖为研究背景,针对板岩在不同应力下的损伤力学特性,在MTS815伺服试验系统上开展了常规三轴压缩试验。结果表明:(1)板岩的起裂应力比相对于闭合应力比与损伤应力比受围压的影响较小,且随着围压增大,板岩表现出脆性降低、延性增强的状态;(2)随着围压的升高,扩容应力和抗压强度均增大,体积扩容点前移,两者的比值先降低后稳定在84%左右;(3)泊松比、变形模量和弹性模量与围压的增大成正比,变形模量普遍大于弹性模量,且后者受围压的影响更加显著,通过m-c包络线法和σ1-σ3最佳关系曲线法求得板岩黏聚力为35.04 MPa,内摩擦角为40.42°;(4)板岩破坏过程中加载总能量与耗散能均增大,两者的差值呈“月牙状”;弹性能先升高后降低,在峰值应力处达到存储极限;峰值应力前的损伤演化可分为损伤起始、损伤稳定累计和损伤加速三个阶段,且在相同损伤程度下,高围压环境中的试样会产生更大的应力变形。
Taking the excavation of a tunnel in western Sichuan as the research background, conventional triaxial compression tests are conducted on the MTS815 servo testing system to investigate the damage mechanical characteristics of slate under different stresses. The experimental results show that: (1) The initiation stress ratio of slate is less affected by confining pressure compared to the closure stress ratio and damage stress ratio; As the confining pressure increases, the slate exhibits a state of reduced brittleness and increased ductility. (2) As the confining pressure increases, both the expansion stress and compressive strength increase, and the volume expansion point moves forward. The ratio of the two first decreases and then stabilizes at around 84%. (3) The Poisson's ratio, deformation modulus, and elastic modulus are directly proportional to the increase in confining pressure. The deformation modulus is generally greater than the elastic modulus, and the latter is more significantly affected by confining pressure; By using the m-c envelope method and σ1-σ3 the optimal relationship curve method was used to obtain a cohesive force of 35.04 MPa and an internal friction angle of 40.42° for the slate. (4) During the process of slate failure, both the total loading energy and the dissipated energy increase, with a crescent-shaped difference between the two; The elastic energy first increases and then decreases, reaching the storage limit at the peak stress; The damage evolution before peak stress can be divided into three stages: damage initiation, stable accumulation of damage, and damage acceleration. Under the same degree of damage, specimens in high confining pressure environments will produce greater stress deformation.
[1] 崔光耀, 魏杭杭, 王明胜. 高地应力强风化炭质板岩隧道大变形控制现场试验研究 [J]. 现代隧道技术, 2022, 59 (3): 183-189,200.
[2] Tang Y, Zhang H, Xu J, et al. Mechanism andeffect of stress level on the generalized relaxation behavior of tage tuff under triaxial compression[J]. Rock Mechanics and Rock Engineering, 2023, 56(9): 6173-6187.
[3] Liu J F, Qi X S, Yang J X, et al. Failure transition of shear-to-dilation band of rock salt under triaxial stresses[J]. Journal of Rock Mechanics and Geotechnical Engineering, 2024, DOI: 10.1016/j.jrmge.2023.03.015
[4] Hao X J, Wang S H, Xu Q S, et al. Influences of confining pressure and bedding angles on the deformation, fracture and mechanical characteristics of slate[J]. Construction and Building Material, 2020, 243: 118255.
[5] 杨意德,贾淯斐,梁冰,等. 层理倾角对岩石抗剪强度参数影响的试验研究 [J]. 采矿技术, 2019, 19 (6): 77-81.
[6] 赵宁宁, 李二强, 冯吉利. 层状板岩单轴压缩试验及数值研究[J].中南大学学报(自然科学版), 2022, 53(10): 3978-3988.
[7] 刘运思, 何楚韶, 王世鸣, 等. 冲击荷载下层状板岩拉伸破坏及能耗规律研究[J]. 应用力学学报, 2021, 38(4): 1373-1382.
[8] Zhao N, Feng J, Ma T. Investigation on thefracture properties of layered carbonaceous slate: Experiment and numerical simulation[J]. Geofluids, 2022,2022:1-15.
[9] Meng L B, Li T B, Cai G J. Temperature effects on the mechanicalproperties of slates in triaxial compression test[J]. Journal of Mountain Science, 2017,14(12):2581-2588.
[10] 李二强, 张龙飞, 赵宁宁, 等. 风化作用下层状板岩I型断裂特性试验研究[J]. 中南大学学报(自然科学版), 2022, 53(4): 1406-1415.
[11] 郭新新, 朱安龙, 王万平, 等. 高应力炭质板岩隧道大变形特征及其机理分析[J]. 隧道与地下工程灾害防治, 2021, 3(4): 29-39.
[12] 王智佼, 谢迪, 范晋琰, 等. 西部某强风化炭质板岩隧道变形力学机制及大变形控制方法研究[J]. 地质力学学报, 2023, 29(5): 648-661.
[13] Lu H, Bao W, Yin Y, et al. Experimental study on multi-scale damage and deterioration mechanism of carbonaceous slate under freeze-thaw cycles[J]. Bulletin of Engineering Geology and the Environment, 2023, 82(12):458.
[14] Chen Z, He C, Wu D, et al. Fracture evolution and energy mechanism of deep-buried carbonaceous slate[J]. Acta Geotechnica, 2017, 12(6): 1243-1260.
[15] 李玉平, 田世雄, 胡玉琨, 等. 炭质板岩隧道大变形段“围压拱”支护方案[J]. 地下空间与工程学报, 2020, 16 (增1): 137-146.
[16] Zhou P, Jiang Y, Zhou F, et al. Stability-evaluation method and support structure optimization of weak and fractured slate tunnel[J]. Rock Mechanics and Rock Engineering, 2022,55(10):6425-6444.
[17] 张海太, 任高攀, 万志文, 等. 薄层炭质板岩地层隧道围岩大变形特征及支护方法研究[J]. 地下空间与工程学报, 2020, 16 (增1): 457-464.
[18] Martin C D,Chandler N A. The progressive fracture of lac du bonnet granite[J].International Journal of Rock Mechanic sand Mining Sciences ＆ Geomechanics Abstracts, 1994, 31(6) :643－659.
[19] 肖桃李, 黄梅, 李新平. 考虑围压效应的深埋大理岩强度变形特性研究[J]. 地下空间与工程学报, 2018, 14(2): 362-368.
[20] 赵坚, 李海波. 莫尔-库仑和霍克-布朗强度准则用于评估脆性岩石动态强度的适用性[J]. 岩石力学与工程学报, 2003(2): 171-176.
[21] 杨同, 徐川, 王宝学, 等. 岩土三轴试验中的黏聚力与内摩擦角[J]. 中国矿业, 2007(12): 104-107.
[22] Zhou T, Qin Y, Ma Q, et al. Aconstitutive model for rock based on energy dissipation and transformation principles [J]. Arabian Journal of Geosciences, 2019, 12(15): 492.
[23] 张佳. 岩石压缩能量演化规律及非线性演化模型研究 [J]. 煤炭科学技术, 2021, 49 (8): 73-80.
[24] 张黎明, 高速, 任明远, 等. 岩石加荷破坏弹性能和耗散能演化特性 [J]. 煤炭学报, 2014, 39 (7): 1238-1242.
[25] 张强星, 刘建锋, 曾寅, 等. 膏岩三轴压缩声发射特征及损伤演化研究[J]. 地下空间与工程学报, 2019, 15 (5): 1323-1330.
