Influence of Cutting Tools on Filter Cake Formation during Slurry Shield Tunnelling

Jiahua Mao,Dajun Yuan,Dalong Jin,Shengnan Liu 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.6

The filter cake on excavation face would be destructed periodically by cutting tools during slurry shield tunneling. The broken filter cake has a risk for face stability. The influence of cutting tools on filter cake was studied in this paper. A slurry-soil interaction model based on a multiphase flow theory which considers the solid particles and fluid in slurry was developed. The whole process of slurry penetration and filter cake formation on the excavation face of slurry shield can be described by this model. The motion state of cutting tools can be combined with this model and the effect of cutting tools on the slurry-soil interaction and pressure transfer mechanism was analyzed. Subsequently, the comparative calculations were presented to discuss the influence of tunneling parameters and the design of cutting wheel on filter cake formation during slurry shield tunnelling. The results indicate that the total area of filter cake on excavation face increases with the decreasing of revolutions per minute of cutting wheel and shield machine advance rate. The area ratio of filter cake on the center of excavation face always larger than other zone due to the lesser amount of cutting tools within one track in the center of cutting wheel. The results can provide a better understanding of how to set the shield tunneling parameters and design the layout of cutting tools for the stability of tunnel face.

Experimental Study on Interaction between Slurry and Soil on Excavation Face of Shield in Sand Stratum

Jiahua Mao,Dajun Yuan,Binghui Wang,Shengnan Liu,Liping Chen 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

In sandy soil, the timely and effective formation of a filter cake is crucial for maintaining the stability of the excavated face during slurry shield tunnelling. Obtaining real-time information on slurry infiltration and particle migration is challenging, which greatly impacts the formation of the filter cake. Real-time monitoring of slurry infiltration and particle deposition is achieved through the use of electrical resistivity and pore water pressure measurements of the soil. It has been discovered that the primary pathway for slurry infiltration is inevitable in sandy soil, and it is crucial to take note of the persistent slurry leakage resulting from this situation in the shield excavation face. The distribution of slurry particle deposition is highly non-uniform in the penetration direction, with the maximum particle deposition occurring at the slurry-soil interface. However, this deposition is susceptible to disturbance from shield cutting tools, which can compromise the safety of the excavation face. Even if the particle size of the slurry is smaller than the pore size of the sand stratum, the slurry with higher viscosity can still form an internal filter cake. Furthermore, the research indicates that slurry infiltration can induce regular changes in soil electrical resistivity.

Multi-modal Medical Image Fusion Using Deep High-Resolution Representation Learning and Joint Loss

Jiahua Wu(오가화),Hyo Jong Lee(이효종) 한국정보과학회 2020 한국정보과학회 학술발표논문집 Vol.2020 No.7

Safe Range of Retaining Pressure for Three-dimensional Face of Pressurized Tunnels based on Limit Analysis and Reliability Method

Jiahua Zhang,Wei-jun Wang,Dao-bing Zhang,Biao Zhang,Fei Meng 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.11

Based on the existing research, the 3D active and passive failure mechanisms of a pressurized tunnel face are constructed. The nonlinear failure criterion is introduced into the limit analysis by virtue of the tangent technique. By neglecting the randomness of soil parameters, the collapse pressure of active failure and the blowout pressure of passive failure, namely the lower and upper limit of retaining pressure, are obtained along with the failure ranges. On account of the randomness of soil properties, a three-dimensional stochastic model of a pressurized tunnel face is established, and the optimal range of retaining pressure of the pressurized tunnel face is presented on the basis of the multiple correlated failure modes. Taking Changsha Metro Line 2 as an example, the good agreement of the measured data in situ with the reasonable range of retaining pressure verifies the presented method. The combination of limit analysis and reliability method can provide more scientific and reasonable support parameters for the construction of pressurized tunnels in the future.

A Routing Problem in Global Production Planning

Qian Huang,Jiahua Weng,Shunichi Ohmori,Kazuho Yoshimoto 대한산업공학회 2020 Industrial Engineeering & Management Systems Vol.19 No.2

The paper proposes an integrated approach for global production planning of production, transportation, and sales problems wherein transportation routing must be optimized simultaneously. Multi-market, multi-product, multi-plant, and multi-path frameworks comprise the research contexts. The objective of this study is to determine how to maximize total profit with path-selection of marine transportation. Products are transported from plants to markets by marine shippers that are business partners of the manufacturer. Unit production costs from each plant to each market are not constant in this study, changing according to transportation path, and discount policy on each liner. Since the proposed model is a nonlinear problem with a nonconvex objective function and has nonlinear constraints, the model was linearized into a mixed-integer linear problem so that it could be solved with an optimization solver. moreover, computational experiments were conducted. the findings show that, because of transportation routing influences production allocation and sales operations, the proposed integrated approach is proven to be effective at increasing total profit and can be used as a decision support tool to aid global manufacturers to contract with transportation booking companies.

A differential pumping system for the gas attenuator of SXFEL

Junnan LIU,Jiahua CHEN,Chaofan XUE 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Effect of Au film and absorption groups on minority carrier life of porous silicon

Yue Zhao,Linjun Wang,Jiahua Min,Weimin Shi 한국물리학회 2010 Current Applied Physics Vol.10 No.3

In this paper, the samples were prepared with or without metal assistance in different time. The effect of Au film and absorption groups on minority carrier life of porous silicon was studied by using l-PCD measurements,and the result was further proved by FTIR spectra and SEM images. The results were showed that the existed hydrogen-related groups on the surface of porous silicon would decrease the minority carrier life and the grid Au film also can decrease the minority carrier life. The minority carrier life may be controlled by the more effective factor, metal elements or absorption groups.

SrAl₁₂O₁₉:Pr³⁺ nanodisks and nanoplates: New processing technique and photon cascade emission

Nie, Zhaogang,Zhang, Jiahua,Zhang, Xia,Lim, Ki-Soo Cambridge University Press (Materials Research Soc 2009 Journal of materials research Vol.24 No.5

<P>High-quality SrAl12O19:Pr<SUP>3+</SUP> nanodisks and nanoplates were fabricated via a new processing technique based on a modified polymer steric entrapment method. Serious agglomeration and large particle size distribution of final products, which usually occurred in the conventional method, were eliminated completely. The effects of new synthetic processes on the morphology, crystallization, and yield of products and the relevant mechanisms were discussed. As far as we know, SrAl12O19:Pr<SUP>3+</SUP> nanodisks with mean diameter ∼60 nm and thickness between 5 and 10 nm were successfully synthesized for the first time by this low-cost technique. The new synthetic method may provide a general route to synthesize other refractory mixed-oxide nanocrystals. Photon cascade emission involving transitions <SUP>1</SUP>S0-<SUP>1</SUP>I6 followed by <SUP>3</SUP>P0-<SUP>3</SUP>H4 in SrAl12O19:1% Pr<SUP>3+</SUP> nanodisks was investigated. Size-effect-induced blue shift of the 4<I>f</I>5<I>d</I> states of Pr<SUP>3+</SUP> was observed in SrAl12O19:1% Pr<SUP>3+</SUP> nanodisks, in which the quantum efficiency was preserved, as in the bulk counterparts.</P>

Response of egg-pupal parasitoid Fopius arisanus (Sonan) to infochemicals from the host eggs' surface of Bactrocera dorsalis (Hendel)

Qinge Ji,Kang Bi,Jiahua Chen 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.4

To determine host-related infochemicals that facilitate contact between the egg-pupal parasitoid, Fopius arisanus (Sonan), and its host, Bactrocera dorsalis (Hendel), we analyzed the volatiles on the surface of B. dorsalis eggs by hydrocarbon profiling of the hexane extracts using Gas Chromatography–Mass Spectrometry (GC–MS). These analyses resulted in the identification of 12 components from the egg surface. Among these 6 were alkanes (Dodecane, Heneicosane, Docosane, Tricosane, Tetracosane and Pentacosane) and the proportion was 42.79%, 1 was a fatty acid (Palmitic acid) and the proportion was 3.88%, 3 were fatty acid derivatives (Dodecanoic acid methylester, Lauric acid ethyl ester and Ethyl tetradecanoate) and the proportion was 45.92%, and 2 were alcohols (Tetradecanol and Hexadecanol) and the proportion was 7.41%. 9 chemicals were chosen from the above 12 components to study the EAG and behavioral responses of male and female F. arisanus. The results showed that the EAG and behavioral responses of F. arisanus to same chemical had similar trends, and both EAG relative values and lure rates of females were higher than males' generally. However, for Dodecane and Tetracosane the EAG relative values and lure rates showed extremely significant differences between males and females respectively, for Tricosane there was significant difference, for Ethyl tetradecanoate there was no significant difference between males and females of the relative EAG values but of the lure rates there was significant difference. The resultsmaybe provide new insights fromthe chemical relationship between parasitoid and host to biocontrol B. dorsalis using F. arisanus.

Research on Comparison and Evolution Mobile Customers Participate Type in Open Innovation

Zhen Zhang,He Junhui,Jiahua Li 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.8