General Formulas for Calculating Surrounding Rock Pressure of Tunnels and Underground Spaces

Jingsheng Tong 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.4

Through the analysis of the statistical data from a large number of existing tunnels and underground space engineering projects, the limitations of the commonly used formulas for calculating the surrounding rock pressure of tunnels are examined, and the calculated values were compared with the measured values to reveal the differences between them. A model and research approaches that differ from those associated with the commonly used formulas at present are proposed, a calculation method that takes into account multiple objective factors affecting the surrounding rock pressure established, and a general formula for calculating the surrounding rock pressure derived for convenient engineering application. Various factors that influence the surrounding rock pressure are discussed. The values calculated per various commonly used formulas, the values calculated per derived formulas, and the measured values are compared in terms of relative errors. The general formula is then used to extract a general formula for dividing the deep and shallow burial cases, a general formula for calculating the surrounding rock pressure of deep buried tunnels, and a simplified formula for calculating the surrounding rock pressure of tunnels with different shapes. This study shows that the values calculated per general surrounding rock pressure formula are very close to the measured values, as demonstrated by the high correlation coefficient and the average error being within a reasonable range, thus verifying the reliability and applicability of the formula. The results can provide useful guidance and reference for the design and construction of tunnels and underground spaces.

Research on Application of Multi-factor Surrounding Rock Pressure Calculation Theory in Engineering

Jingsheng Tong 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.6

Based on the multi-factor surrounding rock pressure calculation theory, the values of surrounding rock pressure and construction safety and stability coefficients corresponding to different construction methods required by engineering design and construction could be quickly and conveniently calculated with the derived general formula, so as to guide and optimize the design and construction scheme. In this paper, the influence of lateral load coefficient on surrounding rock pressure was analyzed and verified, and the calculation method and application range of lateral load coefficient were proposed. Meanwhile, according to the multi-factor surrounding rock pressure calculation theory, an arched precast member was proposed, which was assembled into an optimal and reasonable honeycomb-like stress structure, and applied in the support of tunnel and underground space. It could improve the construction technology of composite lining by taking the advantage of the common load bearing of surrounding rock and support. In addition, with the theory, the application of arched precast member in the support of deep foundation pit has simplified the setting of lateral support of deep foundation pit in the horizontal direction, which is an innovative construction method for deep foundation pit support using prefabricated assembly components. Certainly, the calculation theory should be further studied, and the dynamic change of surrounding rock pressure after excavation under various adverse geological conditions should be accurately analyzed and verified by means of monitoring and measurement, which should be reasonably connected with the current Code for popularization and application. It is hoped that the study of the calculation theory and its application in engineering practice can provide useful guidance and help for the design and construction of tunnel and underground space.

Three-dimensional digitalization modeling characterization of pores in high-rank coal in the southern Qinshui basin

Shiqi Liu,Shuxun Sang,Jingsheng Ma,Xin Wang,Yi Du,Tian Wang 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.1

Pore connectivity is an important property of coal. To explore the connectivity of pore-fractures in terms of macropores and mesopores in high-rank coal, two coal samples collected from the coal seam #3 in the southern Qinshui basin were selected. A pore-fracture network model of high-rank coal on the nanometer (10–100 nm) to micrometer (0.1–10 μm) scale is constructed, and key parameters are extracted using the 3D (three-dimensional) digital spatial characterization based on 3D scanning with FIB-SEM (Focused Ion Beam Scanning Electron Microscopy). Then, the connectivity of the pore-fractures and the contribution of pores with different genetic types to the connectivity of the high-rank coal are confirmed. The results show that the pores and throats of high-rank coal in coal seam #3 in the southern Qinshui basin are very narrow, with predominant mesopores < 50 nm in width. The tortuosity of the coal samples is low, an the cross-section is predominantly square and triangular in shape, which means that the capillary resistance is small. The connectivity of the pores is poor, and mesopores play an important role in the pore connectivity. Linear differential shrinkage pores are the main connected pores on the nanometer scale and communicate with irregularly rounded and elliptic differential shrinkage pores, secondary pores, and mineral pores. The types and contents of the minerals in coals determine the morphological characteristics and degree of development of the differential shrinkage pores, and have an important influence on the pore connectivity in high-rank coal. The content of quartz determines the degree of development of the linear differential shrinkage pores, and is the primary reasons for the differences in the connectivity of the two samples.

Effects of rapid thermal annealing on structural, magnetic and optical properties of Ni-doped ZnO thin films

Xing Zhao,Erjia Liu,R.V. Ramanujan,Jingsheng Chen 한국물리학회 2012 Current Applied Physics Vol.12 No.3

XPS depth profiles were used to investigate the effects of rapid thermal annealing under varying conditions on the structural, magnetic and optical properties of Ni-doped ZnO thin films. Oxidization of metallic Ni from its metallic state to two-valence oxidation state occurred in the film annealed in air at 600 ℃, while reduction of Ni2+ from its two-valence oxidation state to metallic state occurred in the film annealed in Ar at 600 and 800 ℃. In addition, there appeared to be significant diffusion of Ni from the bottom to the top surface of the film during annealing in Ar at 800 ℃. Both as-deposited and annealed thin films displayed obvious room temperature ferromagnetism (RTFM) which was from metallic Ni, Ni2+or both with two distinct mechanisms. Furthermore, a significant improvement in saturation magnetization (Ms) in the films was observed after annealing in air (Ms= 0.036 mB/Ni) or Ar (Ms= 0.033 mB/Ni) at 600 ℃ compared to that in as-deposited film (Ms = 0.017 mB/Ni). An even higher Ms value was observed in the film annealed in Ar at 800 ℃ (Ms= 0.055 mB/Ni) compared to that at 600 ℃ mainly due to the diffusion of Ni. The ultraviolet emission of the Ni-doped ZnO thin film was restored during annealing in Ar at 800 ℃, which was also attributed to the diffusion of Ni.

FeRh-FePt exchange spring media for Heat Assisted Magnetic Recording

Wei Chuan Goh,Wai Lwin Phyoe,JingSheng Chen 한국자기학회 2007 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Structural and magnetic properties of Si1−xGex thin films implanted with Fe ions

Li Wang,Deng-Lu Hou,Jingsheng Yu,Wengang Wei,Cong-Mian Zhen,Li Ma,Fengchun Hu,Chao Wang 한국물리학회 2013 Current Applied Physics Vol.13 No.4

A series of Si1-xGex (x = 1, 0.848, 0.591, 0.382, 0.209, 0.064, 0) thin films prepared by ion beam sputtering were implanted with Fe ions to different doses using the metal vapor vacuum arc technique. X-ray absorption fine structure (XAFS) was used to characterize the local microstructure around the Fe atoms in Fe-doped Si1-xGex samples. Structural analysis showed that for annealed samples of Ge-rich thin films (including pure Ge) implanted with low doses of Fe ions, almost all the Fe ions substituted at Ge sites. However, an anti-ferromagnetic Fe6Ge5 impurity phase existed in the annealed samples implanted with high doses of Fe. It was also found that the solubility of Fe ions was highest in pure Ge films and that with increasing Si concentration, the solubility decreased. Magnetic analysis showed that for the as-implanted and annealed samples of Ge-rich thin films implanted with Fe ions, room-temperature ferromagnetism was strongest in the pure Ge series of samples and that as the Ge concentration decreased, the ferromagnetism at room temperature weakened. In addition, annealing could increase the number of Fe ions at substitution sites, which resulted in the observed increase in the saturated magnetization after annealing. Experiment and theoretical analysis showed that the ferromagnetism of Fe-doped Ge-rich Si1xGex thin films samples originated from the s, ped exchange interactions between the Si1-xGex matrix and those Fe ions which substituted at Ge sites and that the ferromagnetism was mediated by carriers.

Genome shuffling improved acid-tolerance and succinic acid production of Actinobacillus succinogenes

Shumeng Hu,Ying You,Feifei Xia,Junmei Liu,Weichang Dai,Jingsheng Liu,Yuhua Wang 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.3

Succinic acid is widely applied to chemical,pharmaceutical, food, and agricultural industries. With therapid development of these industries, a great demand ofsuccinic acid is required. The acid-tolerance and succinicacid production of Actinobacillus succinogenes strain wereimproved by using genome shuffling. Results showed thatone modified strain AS-F32, with the best acid resistanceand the highest succinic acid production, was obtained after3 cycles of genome shuffling. The minimum growth pH ofAS-F32 was 3.5, and the acid production and cell dryweight were 5.1 and 4.8 g/L in flask, improved 2.6 and1.85 times over the start strain As-R2. Furthermore, thesuccinic acid yield of As-32 was 31.2 g/L and the dry cellweight was increased 44.4% by maintaining pH 4.8 with7.0 M NH4OH in 5 L bioreactor, increased 1.1 times thanthe original strain As-R2.

A novel ‘‘green’’ solvent to deeply purify quartz sand with high yields: A case study

Xiaoxia Li,Tihai Li,Jianxiong Gao,Houquan Huang,Linbo Li,Jingsheng Li 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.35 No.-

A novel ‘‘green’’ solvent for removing iron and aluminum impurities simultaneously from quartz sandwas presented to replace the outdated industrial strong acids. The solvent is a ‘‘green’’ mixturecomprised nontoxic, renewable acids and a very diluted hydrochloric acid. The new solvent cansignificantly reduce the pollution caused by residual acids and remain the high efficiency in removingimpurities and is harmless to the target product as well. The final optimum removing rate was up to79.1% and 42.3% respectively if its leached residue was washed, then leached again in a 4 g/l Na2CO3solution under ultrasound for 25 min.

Endoscopic Hemostasis in Nonvariceal Upper Gastrointestinal Bleeding: Comparison of Physician Practice in the East and the West

Tang, Shou-jiang,Lee, Sun-Young,Hynan, Linda S.,Yan, Jingsheng,Riley, Fransell C.,Armstrong, Luis,Rodriguez-Frias, Edmundo,Xu, Lin,Pruna, Ernesto,Lara, Luis F.,Sreenarasimhaiah, Jayaprakash,Choi, Kyoo Springer-Verlag 2009 Digestive diseases and sciences Vol.54 No.11

Production of Transgenic Goats by Sperm-mediated Exogenous DNA Transfer Method

Zhao, Yongju,Wei, Hong,Wang, Yong,Wang, Lingbin,Yu, Mingju,Fan, Jingsheng,Zheng, Shuangyan,Zhao, Cong Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.1

In this study, the production of transgenic goats using sperm to integrate exogenous DNA and artificial insemination (AI) was carried out and the technical protocols for sperm-mediated gene transfer (SMGT) in the goat were optimized. The standard sperm parameters and the ability to bind foreign genes were assessed to select suitable sperm donor bucks. A total of 134 oestrous does were divided into 4 groups and inseminated using different methods and sperm numbers. The does of Groups I to III were inseminated with fresh semen ($1-2\times10^{7}$ and $10^{6}$ sperm) or frozen-thawed semen ($10^{6}$ sperm), respectively, through conventional intra-cervical AI, and the does of Group IV with frozen-thawed semen ($10^{6}$ sperm) through intrauterine AI. Total genomic DNAs were extracted from ear biopsies of the offspring. The presence of $pEGFP-N_{1}$ DNA was screened by PCR and then by Southern blotting analysis. A total of 76 live kids were produced and 8 kids were tested transgene positive on the basis of agarose gel electrophoresis of the PCR-amplified fragment. Southern blotting analysis of the samples showed 5 positive kids. A transgenic ratio of 10.53% was detected using PCR and 6.58% using Southern blotting. The positive kid rate assayed by PCR and Southern blotting of frozen-thawed goat semen was 3.61% and 9.27% higher than that of untreated semen. The results show that transgenic goats can be produced efficiently by the method of artificial insemination using sperm cells to integrate the exogenous DNA and intrauterine insemination allowed low numbers of DNA-transfected spermatozoa to be used, with satisfactory fertility.