Anisotropic Characteristic of Irregular Columnar-jointed Rock Mass Based on Physical Model Test

Zhinan Lin,Weiya Xu,Huanling Wang,Jiuchang Zhang,Wang Wei,Rubin Wang,Hua Ji 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.5

Columnar joint is a special geological structure with self-organized joint network which separates the rock into an assemblage of blocks. The mechanic characteristics of irregular columnar-jointed rock mass (ICJRM) are dependent not only on the intact rock material but also on unique types of columnar joints. In effort to understand the anisotropic mechanic characteristics of ICJRM by the inherent anisotropic nature of the jointed structure, we conducted a series of uniaxial compression tests. Experiments were performed on an artificial ICJRM of 50 mm in diameter and 100 mm high. The “intact material” consisted of cement mortar and the columnar joints of photosensitive resins. The columnar joint in the specimen was made into six different orientations: 0°, 30°, 45°, 60°, 75°, and 90°, respectively, so observe the deformation behavior and failure modes of ICJRM with different various angles between the loading orientation and columnar joint were observed. Based on the analysis of the test results, the uniaxial compression strength and elastic modulus of ICJRM showed strong anisotropic behavior along with a special “U” shape in response to the angle between the loading orientation and columnar joint. Furthermore, the failure modes of ICJRM was observed.

Permeability Anisotropy of Columnar Jointed Rock Masses

Lifang Zou,Weiya Xu,Guotao Meng,Yu Ning,Huanling Wang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

This paper investigated the anisotropic permeability of columnar jointed rock masses at Baihetan hydropower station in Southwest China. Discrete element analysis is conducted to evaluate the hydraulic Representative Elemental Volume (REV) size of jointed rock masses. It is found to be 5m×5m and it is seven times of the column length. Research shows that permeability tensor of the jointed rocks exists. The maximum principle permeability is 3.47 × 10−14 m2 and the minimum principle permeability is 1.39 × 10−14 m2. The direction of maximum principle permeability is 72 degrees anticlockwise from the positive x- axis direction, which is along the same direction of the column length. A continuum hydro-mechanical coupling analysis is carried out on water infill of a tailrace tunnel in columnar basalt. An equivalent anisotropic mechanical model is applied in the numerical simulation. Anisotropic deformation and anisotropic permeability characteristics are investigated under the condition that the angle between maximum principle stress axis and maximum principle permeability axis is 72 degrees. Results show that anisotropic seepage field has an effort on anisotropic deformation field.

Determination of Strength and Deformation Properties of Columnar Jointed Rock Mass Using Physical Model Tests

Zhinan Lin,Weiya Xu,Wei Wang,Huanling Wang,Rubin Wang,Hua Ji,Jiuchang Zhang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.9

The strength behavior and deformation modulus of columnar jointed rock mass have been investigated by conducting a series of uniaxial compressive tests, along with consideration of columnar joint effect. The tests have been performed on the artificial physical model samples, incorporating different angles β (which was the between the loading direction and axial direction of the columns) and heights of specimen. Columnar joint is a special geological structure with self-organized joint network which separates the rock into an assemblage of blocks. Due to the special joint network, the anisotropic characteristics of columnar joint rock mass is very remarkable. The physical model consisted of “intact rock” and “jointed filler”, replaced by cement mortar and white cement, respectively. The angle β were set to 0°, 15°, 30°, 45°, 60°, 75° and 90°, respectively, and the heights of specimen were set to five different values. Through the test, failure strength and failure modes of columnar joint rock mass with different angles β were observed. Based on the analysis of the test results, the uniaxial compression strength and average modulus of columnar joint rock mass showed strong anisotropy, showing a special “U” shape in terms of loading orientation. The size effect of columnar jointed rock mass was very typical, and the failure mode of columnar joint rock mass were analyzed. Furthermore, the relationship between failure strength and joint factor was studied.

Numerical Investigation of the Influence of Rock Characteristics on the Soil-Rock Mixture (SRM) Slopes Stability

Shiqi Liu,Huanling Wang,Weiya Xu,Zhichao Cheng,Zhipeng Xiang,Wei-Chau Xie 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.11

Soil-rock mixture is a widely distributed geological material in mountainous regions, where slope stability is an important issue. To investigate the influence of rock on slope stability, firstly, rocks in SRM are generated and then SRM slope models are simulated based on the finite difference method (FDM). The impact of various characteristics of rocks on slope factor of safety (FOS) is studied systematically by using the reduced strength method. The characteristic of rock considered include rock content, number of rock edges, aspect ratio, rock size and inclination of rock. The simulations indicate that increasing the rock content can prevent the development of high strain region and improve slope stability. However, the aspect ratio of rock has negligible impact on the mean value of FOS. For slopes with 45o slope angle, rocks with 45o angle of inclination result in smooth potential sliding surface, whereas rocks with 135o angle of inclination lead to more tortuous potential sliding surfaces. Statistical indices are utilized to analyze the results of numerical modelling.

Coal dust exposure induces proliferation and migration of human bronchial epithelial cells

Li Amin,Zhang Yinci,Wang Ruikai,Xu Ruyue,Ma Yongfang,Song Li,Cao Weiya,Xiaolong Tang 대한독성 유전단백체 학회 2023 Molecular & cellular toxicology Vol.19 No.2

Background Coal dust exposure has caused a variety of lung diseases. In addition to genotoxicity and cytotoxicity, other biological changes caused by coal dust (CD) exposure need further study. Objective To observe the cellular transformation eff ects of CD exposure and explore its underlying molecular mechanism, human bronchial epithelial cells (BEAS-2B) were cultured with continuous CD exposure. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay, colony formation assay, wound healing assay, next-generation sequencing (NGS) and western blotting were performed to observe the cell proliferation, migration, genomic transcription and pathological signaling pathways. Results We demonstrated that BEAS-2B cells with long-term chronic CD exposure show accelerated proliferation rate and enhanced migration ability, and have altered gene expression profi les and aberrant activation of EGFR/Raf/ERK and PI3K/ AKT/mTOR pathways. Conclusions The results indicate that chronic CD exposure could induce abnormal proliferation and migration of BEAS-2B cells, lead to the transformation potential of human bronchial epithelial cells.

Correlation between red blood cell distribution width/platelet count and prognosis of newly diagnosed diffuse large B-cell lymphoma

Xiaobo Liu,Yanliang Bai,Ying Liu,Weiya Li,Yabin Cui,Jinhui Xu,Xingjun Xiao,Xiaona Niu,Kai Sun 대한혈액학회 2023 Blood Research Vol.58 No.4

Background Red blood cell distribution width/platelet count ratio (RPR) is a reliable prognostic assessment indicator for numerous diseases. However, no studies to date have examined the relationship between RPR and the prognosis of diffuse large B-cell lymphoma (DLBCL). Therefore, this study aimed to investigate the correlation between RPR and the clinical characteristics and prognosis of patients with diffuse large B-cell lymphoma. Methods We retrospectively studied 143 patients with newly diagnosed DLBCL and used the median value as the RPR threshold. We also investigated the correlation of pretreatment RPR level with clinical characteristics and its impact on DLBCL prognosis. Results Using the median value as the cut-off, patients with DLBCL were divided into a low RPR group (<0.0549) and a high RPR group (≥0.0549). Patients in the high RPR group were older, had a later Ann Arbor stage, were prone to bone marrow invasion, and had a higher National Comprehensive Cancer Network International Prognostic Index score (P < 0.05). A survival analysis showed that progression-free survival (PFS) (P =0.003) and overall survival (OS) (P <0.0001) were significantly shorter in the high versus low RPR group. A multifactorial Cox analysis showed that bone marrow invasion and elevated lactate dehydrogenase (LDH) were separate risk factors for PFS (P <0.05), while an RPR ≥0.0549 and elevated LDH were separate risk factors for OS (P <0.05). Conclusion A high RPR (≥0.0549) in patients with newly diagnosed DLBCL is an independent risk factor for a poor prognosis.