卸荷柱状节理玄武岩力学特性研究
发布时间：2018-11-02 06:49
【摘要】：在建总装机量第一的金沙江白鹤滩水电站,开挖揭露出大量柱状节理玄武岩。因柱状节理玄武岩结构的特殊性,有必要对卸荷柱状节理玄武岩也即柱状节理玄武岩卸荷层的力学特性展开深入的研究。本文通过资料搜集、现场试验及声波测试等手段,在坝址区柱状节理玄武岩卸荷松弛特征的基础上,对卸荷柱状节理玄武岩的变形和强度特性展开了研究,论文主要工作内容如下:1、华东院长期对柱状节理玄武岩平硐及坡面岩体声波测试结果表明卸荷松弛具有时效性、尺寸效应:小尺寸时,随着尺寸的增大,松弛深度增大,较大尺寸时,松弛深度不再增大;柱状节理玄武岩松弛深度基本在0.6~2.9m左右;错动带对岩体松弛有一定的影响。2、变形特性:刚性承压板试验结果显示白鹤滩卸荷柱状节理玄武岩变形模量具有明显的各向异性,且与应力水平和围压相关。三轴变形试验结果同样表明:卸荷柱状节理玄武岩变形模量的各向异性受围压水平的影响;正压力水平对变形模量的影响体现为应力与应变关系非线性;卸荷回弹变形曲线具有显著非线性。3、强度特性:通过现场三轴试验,得到白鹤滩卸荷柱状节理玄武岩的MohrColumb及Hoek-Brown强度模型参数。
[Abstract]:A large number of columnar joint basalts are exposed by excavation of Baihetan Hydropower Station in Jinsha River, which has the highest total installed capacity. Because of the particularity of columnar joint basalt structure, it is necessary to deeply study the mechanical properties of unloading columnar joint basalt. In this paper, the deformation and strength characteristics of columnar joint basalt are studied by means of data collection, field test and acoustic wave test, based on the unloading relaxation characteristics of columnar joint basalt in the dam site. The main work of this paper is as follows: 1. The results of acoustic wave test of columnar joint basalt adit and slope rock mass show that unloading relaxation has time-effect and size effect: when the size is small, the relaxation depth increases with the increase of size. When the size is larger, the relaxation depth will not increase. The relaxation depth of columnar joint basalt is about 0.6 ~ 2.9 m; (2) deformation characteristics: the test results of rigid bearing plate show that the deformation modulus of Baishetan unloaded columnar joint basalt has obvious anisotropy and is related to stress level and confining pressure. The results of triaxial deformation test also show that the anisotropy of deformation modulus of unloaded columnar joint basalt is affected by confining pressure level, the influence of positive pressure level on deformation modulus is nonlinear between stress and strain. The unloading springback deformation curve is significantly nonlinear. 3. Strength characteristics: through field triaxial tests, the MohrColumb and Hoek-Brown strength model parameters of the unloading columnar joint basalt in Baihetan are obtained.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV223
，
本文编号：2305242
[Abstract]:A large number of columnar joint basalts are exposed by excavation of Baihetan Hydropower Station in Jinsha River, which has the highest total installed capacity. Because of the particularity of columnar joint basalt structure, it is necessary to deeply study the mechanical properties of unloading columnar joint basalt. In this paper, the deformation and strength characteristics of columnar joint basalt are studied by means of data collection, field test and acoustic wave test, based on the unloading relaxation characteristics of columnar joint basalt in the dam site. The main work of this paper is as follows: 1. The results of acoustic wave test of columnar joint basalt adit and slope rock mass show that unloading relaxation has time-effect and size effect: when the size is small, the relaxation depth increases with the increase of size. When the size is larger, the relaxation depth will not increase. The relaxation depth of columnar joint basalt is about 0.6 ~ 2.9 m; (2) deformation characteristics: the test results of rigid bearing plate show that the deformation modulus of Baishetan unloaded columnar joint basalt has obvious anisotropy and is related to stress level and confining pressure. The results of triaxial deformation test also show that the anisotropy of deformation modulus of unloaded columnar joint basalt is affected by confining pressure level, the influence of positive pressure level on deformation modulus is nonlinear between stress and strain. The unloading springback deformation curve is significantly nonlinear. 3. Strength characteristics: through field triaxial tests, the MohrColumb and Hoek-Brown strength model parameters of the unloading columnar joint basalt in Baihetan are obtained.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV223
，
本文编号：2305242
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