Table of Content

  

20 April 2017
Volume 47 Issue 2

TBM tunnel segment dislocation due to large deformation and reinforcement mechanism on surrounding rockmass

CHEN Weizhong, CHEN Feifei, ZHAO Wusheng, ZHANG Yuelin

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  1-7.  doi:10.6040/j.issn.1672-3961.0.2017.073

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Soft rock is a complex medium often encountered in rock engineering of major transportation, hydropower, mining engineering construction, squeezing or large deformation is commonly accounted in high in situ stress soft rock underground engineering, which not only affects the construction safety, but also prolongs the construction period and increases the cost. The disaster of large deformation has become a major issue to solve urgently in the field of transportation, water conservancy and deep resources development in China. From the example of Datong River into Huangshui River TBM extrusion segment dislocation caused by the large deformation, repair and control method of large deformation dislocation was suggested from back analysis of field measurement. The results had guiding significance for other expansive mudstone jamming accident and engineering segment dislocation of the turnaround.

Development of a novel rock strength estimation model based on TBM boring performance

CHEN Enyu, DENG Siwen, CHEN Fangming, MA Chishuai

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  7-13.  doi:10.6040/j.issn.1672-3961.0.2017.028

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Based on the analysis of the correlation between in-situ rock strength and TBM performance, a novel rock strength estimation model was proposed. To ensure the in-situ rock strength more accurately, variations of average TBM performance parameters along the tunnel alignment was analyzed in detail, then the fitting relationship with uniaxial compressive strength(UCS)was established. UCS was estimated rapidly by the field penetration index(FPI)based on regression coefficient R²: 0.761 2(field penetration index, FPI)> 0.759 5(thrust)>0.691 5(specific energy, SE)>0.598 6(torque)>0.561 5(penetration). Compared with the previous works on rock strength estimation, the novel rock strength estimation model is more targeted and applicable. The preliminary results of this study provide a more practical and feasible idea for in-situ rock strength estimation of TBM engineerings.

Effect of the velocity pulse on the seismic response of the tunnel

BAI Xianjun, WANG Taixing, WEI Xin, ZHAO Wusheng

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  14-19.  doi:10.6040/j.issn.1672-3961.0.2017.027

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Based on the statistical characteristics of the velocity pulse near the fault and the phase difference, a synthetic method of pulse-like ground motion was proposed. This method could ensure that the synthetic record was non-stationary both in time domain and frequency domain. Based on the N-J hydropower station in Pakistan, the effect of the velocity pulse on the seismic responses of the tunnel were studied by numerical simulation. The results showed that the seismic response of the tunnel was significantly influenced by the velocity pulse. When considering the velocity pulse, the internal forces in tunnel liner increased remarkably, and the damage to the tunnel liner became more serious. The velocity pulse should be considered in anti-seismic design for the tunnels near the faults.

Rockburst evaluation model and application of CW-TOPSIS

HU Quanguang, CHEN Fangming, NING Guangzhong

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  20-25.  doi:10.6040/j.issn.1672-3961.0.2017.097

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To solve the problem that the index weight is difficult to be determined in rockburst disaster assessment model, a combination weighting method of “AHP+entropy weight method” was proposed. The optimization comprehensive weight was established by introducing the Lagrange and Euclidean distance function, ensuring the consistency between the subjective, objective weight and the preference coefficient. Based on the basic theory of TOPSIS, a comprehensive evaluation model of CW-TOPSIS was established and applied to predict rockburst grade. The results of a case study showed that CW-TOPSIS rockburst evaluation model were consistent with the insitu actual conditions which further verified the validity and practicability of the model. The proposed method provided a feasible way for the rockburst prediction from the angle of system evaluation model and gulti-factors indexes.

Energy dissipating rate analysis of N-J hydropower station by pressure relief technique

CHEN Fangming, GU Jianghong, ZHU Bin, WANG Luyu

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  26-31.  doi:10.6040/j.issn.1672-3961.0.2017.098

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In order to study energy dissipating rate of stress relief technique, the drill core pressure relief and blasting analysis of rock burst area of TBM diversion tunnel in Pakistan N-J Hydropower Station were carried out. Borehole pressure relief and pre-spliting blasting of 108 mm diameter drill core were simulated. The borehole pressure relief and pre-spliting blasting was simulated in spacing of 0.5, 1.0, 1.5, 2.0 and 2.5 m. The numerical simulation results showed that the stress relief in TBM tunnel could reduce stress concentration phenomenon. The effect of pre-spliting blasting was much better than drill core pressure relief. Energy dissipation rate of pre-splitting blasting pressure relief reached 27%, while the energy dissipation rate of the simple borehole pressure relief method was only 5.9%. Pre-spliting blasting pressure relief method should be used to reduce the pressure in the rock burst area in project site. In the condition of pre-splitting blasting, the relationship between energy dissipation rate and spacing is basically exponential growth trend. For drill core pressure relief, the relationship between energy dissipation rate and spacing is positive correlation. It is important that layout of drill spacing should be reasonable planning.

Application of the ‘iron grate’ program in the area of rock burst

WANG Taixing, WANG Xikui, ZOU Junpeng, TAN Xuyan

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  32-36.  doi:10.6040/j.issn.1672-3961.0.2017.096

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To reduce the scale of rockburst control, the “iron grate” or “steel bar” scheme was analysed in this paper. The kinetic energy of different rockburst grades was calculated by using the elastic energy density of the surrounding rock mass after tunnel excavation. Based on the back analysis results of NJ-TBM tunnel ground stress and the stress release hole adopting in the engineering area, the maximum rock mass and the maximum velocity of different rockburst zones were determined. A “iron bar or bar row” solution was established by assuming that the maximum rock mass was impacted at the maximum speed to the steel plate / steel bar.Based on the model, the proposed scheme was applied to the strong rockburst, medium rockburst and weak rockburst respectively. The results showed that the program of steel arch spacing 1.5 m and the number of “iron grate”(Φ=20 mm)was 30 at each extension in the strong rockburst area hasnt appeared plastic area. The program of steel arch spacing 1.7 m and the number of “iron grate”(Φ=22 mm)was 20 at each extension in Medium rockburst area, the program of steel arch spacing 2.0 m and the number of “iron grate”(Φ=20 mm)was 20 at each extension in weak rockburst area hasnt appeared plastic area.So the proposed scheme wasnt produced plastic zone in the rockburst area.

Application of “sleeve-connected H-type” buffer in concrete transportation within oversize shafts

LIU Xie, LI Guohua, WANG Ming, MA Chishuai

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  37-40.  doi:10.6040/j.issn.1672-3961.0.2017.095

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Regarding aggregate segregation, excessively fast slipping and poor concrete mix-ability during concrete long distance convey by articulated chute in surge shaft of N-J(NEELUM-JHELUM)hydroelectric project, one kind of “sleeve-connected H-type” buffer was designed and its structure design & operation principle were discussed. Comparative trial and application in site indicate that comparing with original MY·BOX buffer the new one has a simpler structure and cheaper cost, and it can effectively control the concretes dropping speed under high elevation difference and resolve the concrete segregation and damage as well as breaking through for chute, guaranteeing the service life of equipment, construction safety and quality of concrete works, which can also provide reference for similar surge shaft concrete lining project.

Analysis of pre-splitting blasting in rock burst area of N-J hydropower station

NING Guangzhong, HU Quanguang, YAN Xiao, WANG Luyu

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  41-46.  doi:10.6040/j.issn.1672-3961.0.2017.026

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In order to analyse pressure relief of the rock burst area of N-J hydropower station diversion tunnel in Pakistan, the rock burst proneness test of sandstone SS-1 inconstruction area was presented, and the elastic energy index was used as judgingrock burst proneness. The results showed that the construction area was strong rock burst area.It was necessary torelease the stress of drill hole by presplitting blasting.The numerical simulation of presplitting blasting was presented by extended finite element method(XFEM). Considering spacing and tensile strength, the simulation of borehole stress relief included the results that tensile strength was 4,6,8,10 MPa when spacing was 0.5,1.0,1.5, 2.0,2.5 m respectively. The energy dissipating rates and minimum impact forces to drill hole wall were analysed. The results of numerical analysis showed that the energy dissipation rate of presplitting blasting increased with the spacing of drill hole presenting a trend of exponential form. When the calculated impact stress was less than the rock limited dynamic tensile strength, the blasting wouldnt cause the blasting of the blasting wall. In order to ensure the pressure relief effect, spacing of drill hole should be optimal layout.

Grouting reinforcement and excavation stability on super-shallow buried and water-rich sand stratum subway transverse channel

XIA Mengran, LI Wei, FENG Xiao, ZHU Guangxuan, LI Xia

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  47-54.  doi:10.6040/j.issn.1672-3961.0.2017.040

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Against the construction safety of super-shallow buried and water-rich subway transverse channel, laboratory experiments, theoretical analysis and numerical simulation were conducted to select the proper grouting parameter and excavation method, and a series of grouting and excavation method were put forward. Grouting reinforcement could effectively improve the mechanical parameters of sand layer and mechanical properties of soil. The later the support time was, the greater deformation of surrounding rock would be. Pre-reinforcement could effectively improve the physical and mechanical parameters of surrounding rock, reduce the deformation of surrounding rock, and improve the stress-strain relationship. Vault settlement, stress and plastic zone distribution characteristics analysis of excavation step method and CRD(Cross Diaphragm)method were compared, and feasibility of the method was determined. The research results could provide certain references to similar projects.

Integrated advanced geological prediction technology of tunnel and its engineering application

ZHOU Lun, LI Shucai, XU Zhenhao, LI Liping, HUANG Xin, HE Shujiang, LI Guohao

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  55-62.  doi:10.6040/j.issn.1672-3961.0.2016.254

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According to the question that the results from the single advanced prediction method for karst tunnel prediction were different from the actual excavation, the integrated advanced geological prediction technology was proposed to improve the accuracy to unfavorable geologic bodies. Macroscopic geological analysis, TSP(tunnel seismic prediction)method, ground penetrating radar, observation of the tunnel face and the method of advance borehole drilling were combined in advanced geological prediction for tunnel. The integrated advanced geological prediction could give full play to the advantages of each prediction method and improve the accuracy. The research results were successfully applied on advanced geological prediction work in the Liwan highway Moudao Connecting Road Qiyueshan Tunnel. It avoided the casualties and property losses. The large karst cave filled with water and mud in front of the tunnel face of mileage GK0+708~GK0+720 was taken as an example. The process of the integrated advanced geological prediction was detailed and some effective measures were taken to avoid the collapse and the inrush of mud. The study can guide the advanced geological prediction of other similar karst regions.

Object detection algorithm based on Bayesian probability estimation in wavelet domain

LIU Yingxia, WANG Xichang, TANG Xiaoli, CHANG Faliang

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  63-70.  doi:10.6040/j.issn.1672-3961.0.2016.174

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In order to improve the detection algorithm, Bayesian probability estimation model in wavelet domain was built to get a robust threshold, and the detected object could be obtained with the adaptive threshold. Moving Window-Based Double Haar Wavelet Transform for detected image sequence was finished. Bayesian probobility estimation model based on kernel density function was built for low frequency part, and adaptive threshold could be obtained after training and studying. With the threshold to judge the low frequnency part, the binary image could be got. Six video sequences with one targe and multiple targets outdoor and indoor were employed to evaluate the effectiveness of presented algorithm. Experimental results showed that it could give a better detecting results.

Exploring user interest expansion method for recommendation

WANG Xin, LU Jingya, WANG Ying

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  71-79.  doi:10.6040/j.issn.1672-3961.1.2016.099

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An approach of user interest expansion was presented and applied into personal recommendation system, the basic idea was to make some statistics on user's browsing log and clicking log, the user's interest was roughly modelled. The associated relationship from the text similarity, the relevance of language model and potential semantic relationship between the directions of user interest was analyzed, the interest groups using community detection method was identified, the user's interest was enriched appropriately in the same group. By experimental analysis, the impact of user's interest expansion on click rate in personalized recommendations was observed. The click rate had nearly doubled growth.

A visual saliency detection based on background and foreground interaction

ZHAI Jiyou, ZHOU Jingbo, REN Yongfeng, WANG Zhijian

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  80-85.  doi:10.6040/j.issn.1672-3961.0.2016.221

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In order to extract the salient region of image efficiently, a new algorithm model of image saliency detection based on background and foreground interaction was proposed. To find the significant elements in the image, a new model using an interactive feature propagation method to diffuse the significant features was built. The image was segmented into superpixels with different parameters. The salient value of each superpixel was obtained by background and foreground interaction according to a single scale. The final saliency map was obtained by the weighted average fusion of multiple salient values in different scale, and the optimization using the smoothing mechanism. Experimental results showed that the proposed method performed better than the other state-of-the-art methods, which improved the adaptability to the size of salient regions. In addition, our method was proved better not only in restraining the noise, but also in making the salient objects more uniform.

MR image classification based on LBP and extreme learning machine

HE Qijia, LIU Zhenbing, XU Tao, JIANG Shujie

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  86-93.  doi:10.6040/j.issn.1672-3961.1.2016.282

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To solve the problem that theMR brain images are collect from different sources and the pathological fields are varied, a method combining the texture feature extractor which was based on the local binary patterns(LBP)with the extreme learning machine(ELM)classifier was proposed. Mask for region of interest(ROI)was calculated, the image was divided into some sector subareas, LBP histograms were calculatedin every subarea, all the LBP histograms were connected as feature vector and then classified through ELM.Compared with previous methods, the new method could calculate local features, and it was feasible to classify the different sources of MR images and variously lesion images. Some experiments for MR image classification were done, and the accuracy was more than 92% for all samples, the accuracy was more than 93% for positive sample, the accuracy was more than 91% for negative sample. The results showed that the method was available for the varied MR images.

Cardiac cycle estimation of echocardiography with speckle tracking

JIN Peipei, SUN Fengrong, LIU Fanglei, YAO Guihua

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  94-99.  doi:10.6040/j.issn.1672-3961.0.2016.325

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A cardiac cycle estimation method of echocardiography was proposed based on block matching speckle tracking. The position and movement of speckles or speckle pattern within the area of myocardial tissue on echocardiographic images was tracked and recorded, by selecting the regions of interest(ROI)inside the myocardial wall. By calculating the displacement of speckles in the ROI, the length and the start of cardiac cycle was estimated with the sum of absolute differences(SAD)algorithm, and the method was validated by simulated echocardiographic sequences. The experiment results showed a high consistency between theoretical values and actual ones of the cardiac cycle. This method could estimate the length and the start of cardiac cycle effectively and reliably.

Experimental research on the manufacture of chlorine dioxide by sodium chlorite and hydrochloric acid at low concentration

MO Zhengbo, HU Songtao, HU Dedong

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  100-105.  doi:10.6040/j.issn.1672-3961.0.2016.050

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The reaction rate of sodium chlorite was studied at various temperatures and molar concentrations of chlorite and hydrochloric acid at low concentrations. The reaction rate law was established, and macro kinetics formula was obtained. Reaction rates had been found as 1 and 1.39 apparent reaction order with respect to NaClO₂ and hydrochloric acid respectively when the chloride dioxide was prepared at low concentrations of sodium chlorite and hydrochloric acid. The temperature dependence of the reaction was also investigated and pre-exponential Arrhenius parameter as well as activation energy were determined. The theoretical basis was laid for the reactor design and further development and application of the new technique. This study provides a theoretical basis for the design of chlorine dioxide generator.

Fabrication and acid treatment of Bi₇Ti₄NbO₂₁ and their photocatalytic properties

YU Zhenggang, CHANG Ning, ZHAO Genyuan, SHI Chunying, ZHOU Aiqiu

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  106-110.  doi:10.6040/j.issn.1672-3961.0.2016.257

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Aurivillius compound Bi₇Ti₄NbO₂₁ was fabricated by a chemical solution decomposition method(CSD)and acid treated. X-ray diffraction(XRD)analysis revealed that well-crystallized Bi₇Ti₄NbO₂₁ could be prepared with a calcination temperature at or above 550 ℃. Well-crystallized Bi₂Ti₂O₇ with uniform particle sizes was obtained by concentrated nitric acid treatment. Field emission scanning electron microscopy(FESEM)was used to examine the morphology and particles size of as-prepared Bi₇Ti₄NbO₂₁ and acid-treated product Bi₂Ti₂O₇. The results showed that both Bi₇Ti₄NbO₂₁ and Bi₂Ti₂O₇ were highly photocatalytic active for the degradation of organic dye methyl orange under UV light irradiation. The crystallinity and particles size of as-prepared photocatalysts were found to strongly influence the photocatalytic activities. The BTN-550 calcined at 550 ℃ showed the highest activity of as-prepared Bi₇Ti₄NbO₂₁. The Bi₂Ti₂O₇ obtained by acid-treated Bi₇Ti₄NbO₂₁ exhibited remarkable enhanced photocatalytic activity which was superior to that of P25.

Characteristics of PM_1.0 and PM_1.0—2.5in haze days during winter in Jinan

YANG Yumeng, YANG Lingxiao, ZHANG Junmei, WANG Wenxing

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  111-116.  doi:10.6040/j.issn.1672-3961.0.2016.401

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In order to explore the chemical characteristics offine particulate matter(PM)in haze days in Jinan, PM_1.0 and PM_2.5 samples were collected from 15 January to 17 February, 2014 by using mid-volume samplers, chemical components was was analyzed by using ions chromatography and OC/EC analyzer. The results indicated that SO^2-₄, NO^-₃ and NH⁺₄ were the main components in both haze and non-haze days. The three ions contributed more to PM_1.0 and PM_2.5 in haze days compared with that in non-haze days, and the concentrations of the three ions obviously increased in PM_1.0, which suggested that the increase of secondary inorganic aerosol was the main factor of haze formation. Carbon components in PM_1.0 and PM_2.5 ranked second. OC and secondary organic carbon(SOC)increased in haze days than that in non-haze days and enriched in PM with size less than 1um, which suggested that haze days facilitated the formation of SOC. The 72 h backward trajectories analysis indicated that air masses originated from the east of Shandong Province and Beijing-Tianjin area transported near the ground had an extraordinary effect on pollution level in Jinan during haze days.

Preparation, characterization and performance of drag reduction agent used in pipeline of brine mining and transportation

LIAN Lu, HAN Xiangsheng, ZHANG Changqiao, YU Ping, WEI Yunhe

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  117-122.  doi:10.6040/j.issn.1672-3961.0.2016.212

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In order to reduce the energy consumption of the deep brine extraction process, the research on heat resistance and salt tolerance of halogen pipeline drag reduction agent has important practical significance. The synthesis of P(AM/AMPS/AA)adopted redox system by initiated acrylamide(AM)and 2-acrylamide-2-methyl-1-propanesulfonic acid(AMPS)and acrylic acid(AA)in aqueous solution was studied. The optimum experimental conditions were obtained by orthogonal experimental design and online reaction infrared spectrogram. The optimum conditions were as the followings, temperature was 30 ℃, pH value was 1, the monomer mass ratio was 15∶3∶2, the initiator concentration was 0.04%, and the optimized reaction time was 3 h.The structure of P(AM/AMPS/AA)was characterized by FTIR and 1H NMR, and the molecular weight was tested by MALLS. The drag reduction performance of the synthetic polymer was tested on a self-made test pipeline, and the polymer showed better heat resistance and salt resistance, and the drag reduction effect was obvious.When the simulation of brine salinity was 150 g/L, the water temperature was 15 ℃, the flow rate was 950 L/h, the dosage was 20 mg, the polymer drag reduction rate could reach 41.2%. Compared with the existing drag reducing agent, the drag reduction performance was greatly improved, which would have good development and application.

Molecular dynamic simulation on the mechanism of viscosity reduction to asphaltene and resin in heavy oil

CUI Qing, ZHANG Changqiao, XIU Jianxin, XU Shiming, LU Lili

JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2017, 47(2):  123-130.  doi:10.6040/j.issn.1672-3961.0.2016.412

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To in-depth understand the mechanism of viscosity reducing agent to heavy oil and guide the synthesis in laboratory, the Materials Studio software was used to simulate the molecular dynamics of viscosity reducer synthesised by styrene, octadecyl acrylate and maleic anhydride. The results showed that the viscosity reducing agent could effectively remove the associating system by long straight chains and side chains rich in ester and alkyl group, and then improve the stability of asphaltene and resin. Another quaternary polymer synthesized by styrene, octadecyl acrylate, maleic anhydride and acrylamide and its viscosity reduction effect were further simulated, from which could deduce that the quaternary polymer and could behave better than that ternary one. Thus, this kind of quaternary polymer has been set as the target product in the real lab, and Materials Studio can play an important role in guiding synthesis process.