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Mengxia Zhou

Bio: Mengxia Zhou is an academic researcher. The author has contributed to research in topics: Rock mass classification & Arch dam. The author has an hindex of 2, co-authored 2 publications receiving 7 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the effectiveness of overburden consolidation grouting was evaluated in the Baihetan hydropower station on the Jinsha River, and the results showed that this grouting technology can obviously improve the integrity and uniformity of a dam foundation rock mass and reduce the permeability of the rock mass.
Abstract: The dam foundation rock mass, at the Baihetan hydropower station on the Jinsha River, is mainly columnar jointed basalt, with faults and fissures developed. Considering adverse factors such as the unloading relaxation or the opening of the fissures due to excavation blasting, consolidation grouting is needed to improve the integrity of the dam foundation rock mass. According to the physical and mechanical properties of columnar jointed basalt and the continuity of construction, the effectiveness of overburden consolidation grouting is experimentally studied. The results show that this grouting technology can obviously improve the integrity and uniformity of a dam foundation rock mass and reduce the permeability of the rock mass. After grouting, the average increase in the wave velocity of the rock mass is 7.3%. The average improvement in the deformation modulus after grouting is 13.5%. After grouting, the permeability of 99% of the inspection holes in the Lugeon test section had Lugeon values of no more than 3 LU. This improvement is considerable and provides a case to engineering application.

7 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used Lugeon and grouting field tests and geological exploration to investigate curtain grouting characteristics of the Baihetan super-high arch dam foundation, and the results were as follows: (1) the permeability coefficient of the first type of columnar jointed basalt and breccia lava without unloading is 2.5
Abstract: The Baihetan super-high arch dam is constructed under complicated geological conditions, including large-scale columnar jointed basalt (CJB) with closely spaced joints and multiple interlayer and intralayer shear belts at the lower part of dam base, which may increase a risk of seepage in adjacent dam foundations. Therefore, curtain grouting is used to reduce the permeability of dam foundations. Lugeon and grouting field tests and geological exploration were carried out to investigate curtain grouting characteristics of the dam foundation. The findings were as follows: (1) the permeability coefficient of the first type of CJB and breccia lava without unloading is 2 × 10−5 ~ 5 × 10−5 cm/s; that of the second type of CJB without unloading is 2.5 × 10−5 ~ 5 × 10−5 cm/s; and that of the unloaded third type of massive basalt is 1 × 10−5 ~ 3 × 10−5 cm/s. (2) The rock core shows that the slurry caused repeated splitting of the rock mass and widened the cracks of the rock mass, which resulted in plastic deformation of the rock mass. The P ~ Q curve of the five-point Lugeon test shows that the curve shape is turbulent and that the maximum Lugeon value appears at the highest pressure. (3) The phenomenon of low-permeability conditions with a large grout take can be frequently observed. The proportion of the hole stages with a water permeability less than 1 LU and grout take greater than 50 kg/m ranges from 12.5 to 37.5%. The proportion of holes with permeability greater than 10 Lu and grout take greater than 50 kg/m is 0 to 12.5%. The findings from this case study can provide a reference for engineering construction.

6 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a columnar jointed basalt at the foundation of Baihetan Hydropower Station was used as an example for a classification scheme of columnar joints.
Abstract: Rock mass classification is important in preliminary design of geotechnical engineering projects. Using the columnar jointed basalt at the foundation of Baihetan Hydropower Station as an example, this paper presents a classification scheme of the columnar jointed rock. Unlike many common rock masses, an obvious characteristic of columnar jointed rock is that it is discontinuous in geometry while continuous in mechanics. Due to the inapplicability of existing rock mass classification systems, a classification scheme, combined with rock mass integrity, weak plane tightness, and permeability, is proposed. The new classification system has five grades with quantitative factors, which takes into account the features of columnar joints. As an easy-to-use scheme and case study, it would be helpful as a reference in the rock mass classification of similar problems.

20 citations

Journal ArticleDOI
TL;DR: In this article , a series of NMR-based grouting tests in underground fractured sandstone samples based on the low-field nuclear magnetic resonance (LF-NMR) technique was performed to investigate the flow and diffusion mechanism of grout slurry in underground porous rock mass.

15 citations

Journal ArticleDOI
15 Dec 2022-Water
TL;DR: Wang et al. as discussed by the authors summarized and analyzed four aspects of the current situation of curtain grouting technology in deep underground mines: curtain construction conditions, theoretical design and effects, drilling structures, and grouting materials' research and development.
Abstract: In China, mine curtain grouting has become an important technology to ensure the safe and efficient mining of deep mineral resources and protect regional groundwater resources after more than 60 years of development and improvement. This review paper summarizes and analyzes four aspects of the current situation of curtain grouting technology in deep underground mines: curtain construction conditions, theoretical design and effects, drilling structures, and grouting materials’ research and development. In addition, several main problems of curtain grouting technology in deep underground mines are analyzed: planning and construction lag behind; the theory of mine curtain grouting is not mature enough; the investigation into the mechanism of consolidation and deterioration of grout slurry under long-term high pressure is insufficient; there is a lack of research on the long-term effectiveness of monitoring and evaluation, so precise drilling control technology needs further breakthroughs. In addition, the development directions of this technology are put forward from three aspects: precise directional drilling technology; the consolidation mechanism and durability of slurry under multi-field coupling conditions; and long-term dynamic monitoring, evaluation, and early warning for grouting curtain effectiveness. In the future, mine curtain grouting will become an important mine geological guarantee technology for safety, efficiency, accurate, sustainability, and green mining of the Earth’s deep resources.

11 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used Lugeon and grouting field tests and geological exploration to investigate curtain grouting characteristics of the Baihetan super-high arch dam foundation, and the results were as follows: (1) the permeability coefficient of the first type of columnar jointed basalt and breccia lava without unloading is 2.5
Abstract: The Baihetan super-high arch dam is constructed under complicated geological conditions, including large-scale columnar jointed basalt (CJB) with closely spaced joints and multiple interlayer and intralayer shear belts at the lower part of dam base, which may increase a risk of seepage in adjacent dam foundations. Therefore, curtain grouting is used to reduce the permeability of dam foundations. Lugeon and grouting field tests and geological exploration were carried out to investigate curtain grouting characteristics of the dam foundation. The findings were as follows: (1) the permeability coefficient of the first type of CJB and breccia lava without unloading is 2 × 10−5 ~ 5 × 10−5 cm/s; that of the second type of CJB without unloading is 2.5 × 10−5 ~ 5 × 10−5 cm/s; and that of the unloaded third type of massive basalt is 1 × 10−5 ~ 3 × 10−5 cm/s. (2) The rock core shows that the slurry caused repeated splitting of the rock mass and widened the cracks of the rock mass, which resulted in plastic deformation of the rock mass. The P ~ Q curve of the five-point Lugeon test shows that the curve shape is turbulent and that the maximum Lugeon value appears at the highest pressure. (3) The phenomenon of low-permeability conditions with a large grout take can be frequently observed. The proportion of the hole stages with a water permeability less than 1 LU and grout take greater than 50 kg/m ranges from 12.5 to 37.5%. The proportion of holes with permeability greater than 10 Lu and grout take greater than 50 kg/m is 0 to 12.5%. The findings from this case study can provide a reference for engineering construction.

6 citations

Journal ArticleDOI
TL;DR: In this paper , a method for calculating the mean RQD (RQDm) of long stratum is proposed, which is applied to the calculation of rQD of grouting sections.
Abstract: Rock quality designation (RQD) and permeability coefficient are important reference indexes for grouting application. Based on the readily available RQD, RQD is found to have no relationship with the depth of rock stratum, and a method for calculating the mean RQD (RQDm) of long stratum is proposed, which is applied to the calculation of RQD of grouting sections. Through Lugeon and grouting tests on the grouting sections, RQDm of the grouting sections is found to be directly related to the average permeability coefficient, permeability, and units of grouting per amount of rock mass. It is found that RQDm has a symmetrical relationship with permeability and grouting volume as well as a negative exponential correlation with unit grouting volume and average permeability coefficient. According to the curve of RQD varying with depth, the grouting amount at different depths can be obtained by using the fitting formula of unit grouting amount and RQDm.

3 citations