scholarly journals Experimental Study of a New Concrete Admixture and Its Function in Filling and Reinforcing Granite Fissures

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Songnan Ru ◽  
Zuozhou Li ◽  
Handong Liu ◽  
Huaichang Yu ◽  
Chunlei Wei ◽  
...  
Keyword(s):  
Rock Mass ◽  
Water Retention ◽  
Fractured Rock ◽  
Triaxial Compression ◽  
Tensile Tests ◽  
Fractured Rock Mass ◽  
Failure Characteristics ◽  
Basic Performance ◽  
Confining Pressures ◽  
Fractured Rock Masses

A concrete admixture with water retention and superhydrophobic properties was developed according to the high tensile strength, fissure resistance, and antiseepage requirements of concrete linings. Capillary water absorption, early-age anticracking, cube compressive strength, and splitting tensile tests were employed to study the effects of the new concrete admixture on the basic performance of concrete. On this basis, a triaxial compression test was conducted on granite fissures filled with concrete containing the admixture; the stress-strain and failure characteristics under different admixture dosages, confining pressures, and fracture widths were analyzed, and the reinforcement effect of the concrete with the admixture on the fractured rock mass was studied. The results show that the admixture can effectively improve the ability of concrete to resist water and fissures, and the concrete with the admixture significantly reinforced the fractured rock mass. Therefore, it can be widely applied in filling and reinforcing fractured rock masses.

scholarly journals Determining the REV for Fracture Rock Mass Based on Seepage Theory

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Lili Zhang ◽  
Lu Xia ◽  
Qingchun Yu
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Engineering Application ◽  
Existence Condition ◽  
Analysis Tool ◽  
Fractured Rock Mass ◽  
Rock Classification ◽  
Fracture Spacing ◽  
Fractured Rock Masses

Seepage problems of the fractured rock mass have always been a heated topic within hydrogeology and engineering geology. The equivalent porous medium model method is the main method in the study of the seepage of the fractured rock mass and its engineering application. The key to the method is to determine a representative elementary volume (REV). The FractureToKarst software, that is, discrete element software, is a main analysis tool in this paper and developed by a number of authors. According to the standard of rock classification established by ISRM, this paper aims to discuss the existence and the size of REV of fractured rock masses with medium tractility and provide a general method to determine the existence of REV. It can be gleaned from the study that the existence condition of fractured rock mass with medium tractility features average fracture spacing smaller than 0.6 m. If average fracture spacing is larger than 0.6 m, there is no existence of REV. The rationality of the model is verified by a case study. The present research provides a method for the simulation of seepage field in fissured rocks.

Hydro-Mechanical Coupled Analysis of the Variable Permeability Coefficient of Fractured Rock Mass

2013 ◽  
Vol 477-478 ◽  
pp. 531-534
Author(s):  
Yun Jie Zhang ◽  
Tao Xu
Keyword(s):  
Rock Mass ◽  
Permeability Coefficient ◽  
Coupling Effect ◽  
Fractured Rock ◽  
Dynamic Change ◽  
Damage Zone ◽  
Coupled Analysis ◽  
Fractured Rock Mass ◽  
Variable Permeability ◽  
Fractured Rock Masses

Based on the fluid-solid coupling theory, we describe the fractured rock mass as a continuous porous medium and consider the rock mass permeability coefficient a function of the stress and strain. By using the multi-physics coupling analysis software COMSOL, we achieved the dynamic change of permeability coefficient, and found that serious damage due to micro cracking occurred in the excavated damage zone of rock mass due to the yield and failure of rock mass. Corrodingly, permeability will remarkably increase, which is basically consistent with the experimental results. The simulations indicated the "indirect coupling" effect of seepage and stress. Therefore, the coupled analysis of the seepage and stress in fractured rock masses is important for the practical rock mechanics and rock engineering.

scholarly journals Damage Statistical Empirical Model for Fractured Rock under Freezing-Thawing Cycle and Loading

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yifan Chen ◽  
Hang Lin ◽  
Yixian Wang ◽  
Yanlin Zhao
Keyword(s):  
Rock Mass ◽  
Constitutive Relation ◽  
Damage Evolution ◽  
Fractured Rock ◽  
Triaxial Compression ◽  
Fractured Rock Mass ◽  
Cold Regions ◽  
Thawing Cycle ◽  
Conventional Triaxial Compression ◽  
Determination Methods

The natural rock mass prevailingly exists in the form of a fractured rock mass, and freezing-thawing failure of the fractured rock mass is also frequently encountered during geotechnical projects in cold regions. The previous researches and reports in freezing-thawing field principally focused on intact rocks, while rock joints and fractures were rarely considered, which causes great inconvenience to the safety design and stability assessment of engineering. In response to the special climatic conditions of cold regions, the freezing-thawing damage and degradation mechanism of fractured rock were studied in this paper based on existing laboratory experiments and damage mechanics theory. Primarily, a brief review of the progressive damage process of rock in the conventional triaxial compression experiment was given, as well as the determination methods of four characteristic stresses in the prepeak curve. Then, from the microcosmic perspective, the maximum tensile strain yield criterion was used to reflect the microunit strength which was assumed to statistically satisfy the Weibull distribution, deriving the damage evolution equation of fractured rock under the freezing-thawing cycle and load conditions and quantificationally describing the damage evolution law. Consequently, the statistical empirical constitutive relation of fractured rock considering freezing-thawing and loading damages was established. Ultimately, by combining the existing conventional triaxial compression experimental data of freezing-thawing single fractured rocks with the determination methods of characteristic stresses, the relevant constitutive parameters were solved, and the theoretical constitutive relation curves of the fractured rock after freezing-thawing cycles were obtained, which were compared with the experimental results to verify the validity of the established empirical constitutive relation. The study findings can provide a theoretical basis for revealing the freezing-thawing failure mechanism of the fractured rock mass to some extent.

Study of the geometrical size effect of a fractured rock mass based on the modified blockiness evaluation method

2018 ◽  
Vol 11 (11) ◽  
Author(s):  
Qingfa Chen ◽  
Tingchang Yin ◽  
Wenjing Niu ◽  
Wenshi Zheng ◽  
Junguang Liu
Keyword(s):  
Rock Mass ◽  
Size Effect ◽  
Evaluation Method ◽  
Fractured Rock ◽  
Fractured Rock Mass ◽  
Geometrical Size

Application of Borehole Camera Technology in Fractured Rock Mass Investigation of a Submarine Tunnel

2019 ◽  
Vol 83 (sp1) ◽  
pp. 609 ◽  
Author(s):  
Zengqiang Han ◽  
Chuanying Wang ◽  
Sheng Hu ◽  
Yiteng Wang
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Fractured Rock Mass ◽  
Borehole Camera
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