2012 volumne 33 Issue 05
YUAN Wei.,HUANG Maosong,LIU Yilin
Abstract: This paper analyzes the impact of the weak interlayer on the 3D slope stability and failure mode.Example of a classic 3D slope is calculated and the results were compared with the limit equilibrium method toverify the reliability of strength reduction elastoplastic finite element method. And then an example of a 3Dglope with weak interlayer is analyzed, the results show that; the ellipsoid failure surface in the longitudinallength calculated by strength reduction elastoplastic finite element method is larger than the limit equilibriummethod; compared with the 3D homogeneous slope, the factor safety of 3D slope with weak interlayer is muchlower, the scope of failure surface is much larger, the phenomenon of the concentration of plastic strain zone ismore obvious, and the failure mode has many signifcant differences.
XIONG Liangxiao,YU Yu,YU Lijun
Abstract: This paper studies the interlayered rock mass composed of greenschist and marble, the numerical a-nalysis of biaxial compression tests for interlayered rock mass was done by using FLAC3D. Lots of inlluencingfactors such as geometric relationship, volumetric content of marble interlayer and the ratio between lateralstress and axial stress were taken into account in the numerical analysis. The research results show that the bi-axial compression strength when axial loading orientation is parallel to bedding plane and lateral loading orien.tation is perpendicular to bedding plane is largest, and when both axial and lateral loading orientations are par.allel to bedding plane is smallest. The biaxial compression strength will increase firstly and then decrease laterwhen the dip angle of interlayer inereases from 0° to 90° if both axial and lateral loading orientations are paral-lel to bedding plane. The biaxial compression strength will increase firstly and then deerease later when the ra-tio between lateral stress and axial stress increases from 0 to l.0.
ZHANG Zhichao,LIU Hanlong,CHEN Yumin,etc;
Abstract: In the frame of LS-DYNA, the constitutive model which can well describe the dynamic property ofsoil under blast loading was proposed, meanwhile , certain blast-induced earthquake in-situ test was simulated,with the calculated aeeeleration time histories approximate to the recorded dala, which indicates the numericalmethod can provide useful instructions for the in-situ blasting tests in advance and well predicts the blasting re.sults ; based on it , the blasting vibration law through the stratums was analyzed, which reveals that up from theplane where explosive charges lay, the amplitude of horizontal acceleration and velocity minish continuouslywith the decrease of the burial depth ( or the inerease of blast center distance) , while the amplitude of verticalaeceleration and velocity increase first, then decrease and at last remain relatively stable when approaching thefree surface on the ground surface. The numerical endeavour enriches the research on the blast-induced groundmotion and supplies a simple, effective and economic method for the simulation of natural earthquake by milli.second blasting test as well as for the study of seismic response of soil based on it.
ZHU Qunfeng,ZHAO Shiwen,YANG Shouhua,etc;
Abstract: The dredger fill of reclamation projects is characterized by high water content, high compressionand low strength, etc. , and it must be reinforced because of its adverse effects on projects, Based on a practi.cal projeet, the dredger fill is consolidated by means of the vacuum preloading method, Field tests are per.formed by arranging in-situ instruments. Aecording to the results of displacement monitoring, the ground sur.face settlement is 1616 mm, the average degree of consolidation may reach 869 at the end of foundation rein-forcement, and the post-construction settlement is less than 300 mm, The horizontal displacement is less than10 mm. The compressive deformation of dredger fill per unit thickness is 267 mm/m, and it belongs to largedeformation. Aecording to the results of degree of vacuum and power water pressure monitoring, the degree ofvacuum which transmits in the dredger fill foundation has larger frictional loss. The average vane strength ofthe dredger fill after construction is 15. 2 kPa. The indices of the dredger fill are improved to some extent, Thebearing capacity of the foundation is more than 60 kPa, and the foundation consolidation is satisfactory. Theexisting problems in consolidating the dredger fill by use of the vacuum preloading method are discussed. lt issuggested that the consolidation method for the dredger fill should be improved by developing the geotechnicalwater Dox.
ZHANG Qi,LI Kunxuan,WANG Junlin
Abstract: This paper applies intemational general large-scale finite element sotware ANSYS to establish thefinite element model of pile-soil interaction, with a project example, the influence factors for vertical bearingcapacity of large-diameter belled conerete piles are analyzed. Through comparing the simulated results withfield test results, it gets the results of finite is close to the measured value; and then different pile length.belled diameter and belled height influenee on the vertical bearing capacity are simulated and analyzed by thefinite element method. The results show that the belled diameter is larger, the vertical bearing capacity ishigher, the growth is slower when D/d is greater than 2; the belled height is larger, the vertical bearing ca-pacity is higher, but the growth is slow; the length of pile is longer, the vertical bearing capacity is higher,but the growth is slower when the length increase to a certain degree.
CHEN Guixiang,SONG Jiule,ZHANG Zhao
Abstract: Based on the analysis of theory of constraint and eritical chain , this paper firstly illustrates the ad-vantages of critical chain method for dealing with the projeet overrun and project scheduling management. See.ondly , this paper presents the principles and methods about constraint classfication, safety size and buffer sizebased on the Metro scheduling characters. Finally, a computational example is given and the results show thatthe approach is effective.
Feng Yong,Chen Pengju
Abstract: The influence factors of karst collapse are very complex, and they are usually be expressed by cate.gorical data. Although the mathematical theory of quantitative forecasting is quite mature, it has many limitations in processing large scale qualitative data. Therefore, it is necessary to introduce and apply processingqualitative data to forecast the ground collapse risk in karst region, For the improved fuzzy k-modes algorithm,the frequency of each attribute value of each attribute is taken as the cluster’s center, The distance of objectscan be modified by the weight of each attribute. A non-random method is applied to choose the clustering cen-ters , which can ensure the clustering results of complex qualitative data accuracy and reliability. Therefore, inthis paper, based on analysis on the influenee factors in Wuhan karst collapses, the improved fuzzy k-modesalgorithm was used to forecast the hazard potentiality of karst collapse in Wuhan city and good results havebeen obtained, It was found that the application of this model could get good effictiveness and this modelshould be adopted widely.
DU Siyi,SONG Shibo
Abstract: Low strain reflected wave method can detect the defect location of a pile but can’t detect defect se-verity in integrity testing. Relative to the defect position, defect severity is more important, The frequency perturbation theory is adopted to quantitatively detect the foundation pile defects in this paper. The damage identi.fication parameters were defined at first. Then, the formulae and method of quantifying identification defectswere presented by perturbation matrix and dynamics theories of foundation pile. The damage identification pa.rameter was determined by the optimization method, At last, the aceuracy and feasibility of this method wereverified by model pile experiments, and the experiment results show that the method could accurately detectthe severity of pile defects.
Chen Xueli,Wen Minjie,Zhang Bin
Abstract: Assuming that the lining and the soil skeleton are a viscoelastic medium with Kelvin - Voigt modelthe problem of steady state responses of a cylindrical lining struclure with parial sealing subjected to asymmetric radial loading and fuid pressure is investigated using an analytical method in the frequency domain. TheBiot’’s theory and viscoelastic theory are used to describe the saturated soil and lining struclure, respectively.The analytical solutions for the dynamic interaction af saturated viscoleastic soil and lining structure are ob.tained with help of potential functions under partial permeable conditions of the tunnel’s boundary, By utili-.zing, the inner boundary condition of the lining structure and the continuity conditions between the soil and thelining, the unknown coefficients in the expressions of displacement, stress and pore water pressure are deter.mined. On this basis, the influences of the coefhcients of permeable and fluid compressibility, viscous damp.ing coefficient of lining on dynamic responses of the soil and lining are analyzed. A comparative analysis be.tween the results of this paper and existing ones is carried out.
DU Mingfang,DU Weipeng,LIANG Feng,etc;
Abstract: The collapsibility of loess foundation is a potential danger for the buildings safety,and it needs com-pletely or partly eliminating. The PHC pipe pile would arouse the compaction effect and relevant mechanicalcharacters of the soil around the piles during the successive penetrating process of pile group. This paper basedon the PHC pipe piles before and after construction,used in collapsible loess foundation of the Sanmenxia city ,Henan province ,the physical property and collapsible analysis for the soil shows that penetrating process of pilegroup can make the densities of the foundation soil rise , reducing or eliminating the collapsibility of loess.
FU Hua,LING Hua,ZHANG Yali,etc;
Abstract: Comparative tests of rockfill’s sample preparation method between surface vibration compaction andshaking table declared that the maximum dry density which got by surface vibration is higher than that of shaking table’’s. According to the samples by this two different methods, large triaxial tests was conducted whichdeclared that the sample preparation method has an obvious effect on rockfill’s strength and especially on thedeformation behaviors, the indexes which correspond to surface vibration method is better than that of shakingtable’s. It suggested that surface vibration method should be taken as the method of rockfill’s laboratory max.imum dry density determination by taking the process of sample preparation with surface vibration almost simi.lar with the process of roller compaction during earth-rock dam’s construction into account. With the commonuse of heavy roller equipment in earth-rock dam’s construction, the density difference between laboratory andfield can be reduced by improving the vibration power through adjusting the bottom static pressure and prolon.ging the vibration time.
YANG Song,WU Junhua,LU Tinghao,etc;
Abstract: lt is diffeult to measure matric suclion in unsaturated soil, Using saturation as a parameter is valua.ble for unsaturated soil research. A series of improved triaxial compression tests were performed on Yunnan redcohesive soil with different initial saturation degrees and different dry bulk densities. The dilatation occurredfrequently during the tests. When the soil dry bulk density was high, the dilatation of samples with high satu.ration degrees also occurred. The dilatation disappeared when soil dry bulk density was small and saturationdegree was high. The dilatation can be well explained through microscopic mechanism. The dilatation wascaused by lopsided moment and the lopsided moment was caused by pore air pressure. When the soil sampleswith high saturation degrees had small dry bulk densities, the pore air dissolved in the water and the dilatationdisappeared.
LIU Dan
Abstract: Based on consulting high performance at home and abroad and lightweight aggregate concrete tech.nical literature, and on the basis of reasonable selection shale taoli, ordinary Portland cement comprising fivekinds of main ingredients, Pp fiber, polymer emulsion four performance improved agent as a high performanceof lightweight aggregate concrete material, through pp fiber change four ascension agent ratio, test obtained inthe analysis of lightweight aggregate the influencing factors of compressive strength.
ZHENG Yuanxun,HUANG Jingqing
Abstract: In this paper, seismic response of highway runway silt subgrade is analyzed under seismic loads re.spectively based on the coulomb’ s model and Byrne model with FLAC caleulation program based on the practi.cal project, And the influence of seismic intensity on silty soil subgrade seismic response is analyzed in detail.The results show : the roadbed will not be liquelied, when only considering silty soil for the coulomb’ s model,but instantaneous yield may appear at subgrade slope feet. When we consider embankment material for lique-faction model, the pavement may be in a state of tension, embankment bottom may yield, and this may pro.duce subgrade soil liquefaction. Along with the increase of the acceleration peak , the extent of the tension andyield area increases inside the embankment, the likelihood of liquefaction increases, especially when theearthquake acceleration reaches to 0. 1 g, the potential existence of liquefaction of subgrade soil might appear.
WU Mengxi,DENG Qinfang,HUANG Yanbei
Abstract: Levee foundation piping is a complex and dynamie process. For the levee foundation with a thinlayer of relatively impermeable clay over the permeable sand bed, a finite element model is presented to simu-late the souree tracing development of internal soil piping. In eiew of the inlluence of sand concentration on theflow resistance, the coefficient of the equivalent permeability of the pipe flow is given according to the form ofIDarcy formula, ’Thus the simulation of both piping zone and the normal soil zone is unified to the conventionalseepage analysis method. The relationship of soil erosion rate of the pipe wall and the shear stress of the flowis introduced into the balance equation of sediment transportation to simulate the dynamic development of thepiping channel. The dynamic development of the piping channel with time is obtained by the solution of theseepage equation and the sediment transport equation, The simulation of a sand tank test on piping shows that,the model can quantitatively simulate the dynamic development of piping with time.
WANG Nianxiang,ZHANG Weimin,ZHANG Dan,etc;
Abstract: The hydraulie fracturing of high earth - rockfill dams has been widely concered, When the initialand middle diversion tunnels are plugged, the reservoir water level may rise rapidly, and" water wedging” ac.tions may be indueed. The crack in the core and different of initial impounding speed for Changhe Dam aresimulated in centrifuge modeling tests. The faster the initial impounding speed is, the rapider the differenee ofwater pressure of the core near crack increases, and the larger the maximum difference is. The ultimate initialimpounding speed of the dam is 25.5 m/d.
YAO Qiuling,DiNG Liuqian,Vera van Beek,etc;
Abstract: Small seale experiments are performed to simulate piping in dike foundations with heterogeneity.The influence of the heterogeneity on the dike safety has to be investigated by experiments. An addition to therule of Sellmeijer for the heterogeneous configurations has been derived by model validation based on these ex-perimental works. The influence of present piping channels on dike safety has also been analyzed.
WANG Jinlong,ZHANG Jiafa,CUl Haodong,etc;
Abstract: The groundwater is an important factor for the safety of foundation pit, In order to analyse the distri-.bution of seepage field under different calculating conditions with seepage control measures, a typical canalstretch was modeled for construction period of Middle Route Project of $NWT, The numerical simulation re.sults show that the pit safety would decrease with the less permeable layer being excavated step by step and aquifer confined beneath it , so measures should be taken to control and regulate the seepage field. The efficiencyof foundation pit dewatering would be affected by the water recharge boundary, the thickness and permeabilityof the aquifer , the arrangement of dewatering wells, and so on.
ZHANG Guirong,Zhao Bo,RAO Zhigang,etc;
Abstract: According to the problems of bank slope instability and the construction request of green channel,this article analyzes mechanism of ecological bank-protecting, elaborates green ecological governance theoriesof soil bank slope and construction technology of ecological bank-protecting for inland waterway. In view of ec-ological habitat improvement demands , this article put forwards three ecological revetment technologies, inclu.ding the ecological retaining wall of stone cage , flexible bank revetment of ecological bag and geo-cell embank.ment. Based on typical channel project of Dan Jin Li Cao river, two kinds of composite ecological bank-protec-ting technologies for soil bank slope are developed. Based on study of organic combination of vegetation culti-vation, biological habitat restoration technology and ecological slope protection structure, the green ecologicalrecovery technology is built, with the features of stable structure, water permeability and air permeability andbiological diversity. By using commercial software, its deformation stability has been evaluated. The resultsshow that the two kinds of ecological bank-proteeting design scheme can meet the stability requirements offoundation and bank slope, and due to the adoption of flexible bank prevention structure , the design has manyadvantages, such as great adaptive deformation of bank slope, ecological environmental protection, pleasantlandscape , low cost etc.
ZHOU Yang,CHEN Hongwei
Abstract: Conventional dam saturation line inspection methods are limited by the limitations of spatial andtemporal distribution , damage to the instruments, and instruments are not installed, so the application is re.stricted. In view of the fact that soil moisture content is proportional to its electrical resistivity, this article triedto apply high-density resistivity method to detect dam saturation line, this method has no need to drill, and ithas flexibility, a small amount of engineering and high resolution. The actual works based on high-density re-sistivity method for dam saturation line test, and compare with the method of Osmometer, the results show thatthis method can quickly and accurately observed the dam saturation line.
ZHANG Baosen,WANG ZhongFu,TIAN Zhizong
Abstract: New prestressed pipe pile is presented on the basis of analysis of the characteristics of traditionalroekfill groins. Take Huayuankou for example, the eombination of the orthogonal experiment principle of thespur dikes sructure design, the overall displacement law with the parameters change of spur dikes is analyzedby FLAC3D finite difference code. The numerical results show that spur dikes of the horizontal displacement olthe contribution of primary and secondary order as follows: the seour depth of pile length > flow rate > pilespacing and pile diameter > contacts beam size; under the operalion conditions of flood flow 4 000 m’, watervelocity of 3 m/s, the seour depth is 16m operating conditions, the spur dikes structure program of the pilelength 25m 0.6m pile spacing, pile diameter is 600 mm, contact beam size is 0. 6 m x0.6 m is optimal, tothe safely factor of strength reduction method is 1.32.
SUN Changli,DU Xiuzhong,ZHANG Ting,etc;
Abstract: The three-dimensional finite element numerical model of the train running under the effect of vibration of a neighboring hydraulic engineering building power was analyzed. In the calculation , according to thelaw of train running, using a dynamic load function of growing amplitude, and put forward the dynamic analy.sis of the foundation of the force coefficient and damping coefficient calculation method, the calculation in thetrain vibration under dynamie action of a neighboring effects available to the analysis of the similar project toprovide the reference.
PAN Jianbo,WANG Wenchuan,XU Dongmei
Abstract: The agricultural drought is a great threal of agricultural production, and its accurate and efective e-valuation is a key to disaster reduelion decision of agricultural drought resistance of relevant departments. On thebasis of summarizing and analyzing the current evaluation method, a new method is presented based on the opposites unity theorem for drought grade evaluation of irrigation district agriculture. The method proposed satisfiesthe materialist dialectics’ opposites unity law , is precise for the theory and clear for the concept. The compari-son and analysis of results of case demonstrates that the proposed method is elfective, reliable and practical.
ZHU Qiangqiang,ZHANG Guiyun,LIU Wenlong
Abstract: With the expanding applieation of text mining in aetive information serviee, analyzing the inherentcharacteristics of data based on the text data is becoming a current research trend,this paper designs and im.plements a text mining algorithm based on the Hadoop platform which outputs the data aecording to the naturalcorpora adjacent phrase descending frequency ,thus helping the users mine the link between the set in the largequantities of data, In view of the distributed feature of the Hadoop platform, the experimental result shows theefficieney and better speedup.
WANG Jian,Ll Zhibin,LIN Hongfei
Abstract: How to use the social tagging information to improve the effect of query expansion is a current re-search hotspot in the information retrieval field, In this paper, according to the data characteristics of socialtagging systems, we propose a modified social similarity algorithm called “ Weighted SimRank”( WSR ),which is used to improve the effect of query expansion. When the edge weighted values between labels andweb pages are caleulated, the WSR algorithm takes into account the number of co-occurrence users with tagsand web pages as well as the number of different web pages labeled by every same tag. All the experiments arecarried out on a real-world annotation data set which is sampled from the website del. icio. us. The experimen-tal results show that our proposed WSR method can effectively measure the similarity of annotations. Comparedto the other social-annotation-based methods, WSR produces more useful query expansion information and a-chieves better performance.
LIU Wenlong,ZHANG Guiyun,CHEN Zhe
Abstract: Collaborative filtering algorithm is one of the most successful recommender system technology. Thesimilarity calculation is the core of the collaborative filtering algorithm, In view of the poor predication qualityexisting in traditional similarity calculation with sparse data, we propose a similarity calculation method basecon the information entropy between differences of items. First , we weight the entropy by the difference and com.mon evaluation and then normalized it to measure the similarity between items, Verified by experiments with i.tem-based collaborative filtering algorithm, the results show that it improves accuracy of personalized recommendation.
LI Qiang,SHI Lukui,LIU Enhai,etc;
Abstract: Each sample in gene microarray data contains thousands or even tens of thousands of genes. lt isnecessary to reduce the dimension of the data before classifying them for obtaining better classified results.Manifold learning, as a nonlinear dimension reduction method, can discover the intrinsic laws hidden in thehigh dimensional data and has been widely applied in areas such as pattern recognition. A model combiningmanifold learning with classified algorithms was proposed to classify microarray data. In the model, the dimen.sion of microarray data was firstly reduced with some manifold learning method. Then the data reduced the di.mension were classified, In experiments, several manifold learing algorithms ineluding LLE, ISOMAP, LEand L’TSA are combined with three classified methods. And the results are compared with those from directlyclassifying high dimensional data. Experiments showed that the classification accuracy was great improved withthe proposed model. Moreover, the execute elficieney of classification algorithms was also greatly inereased.
ZHANG Qinghua,LI Hong,SHEN Wen
Abstract: In this paper, research and analysis on the basis of the l)ijkstra algorithm, the Dijkstra algorithm byintroducing the vertex of cut sets and cut the vertex of idea to improve the Dijkstra algorithm, this method firsvertex eut-set or cut vertex to the original problem is decomposed into multiple sub-graph, then the shortes!path on each sub-graph parallel to the shortest path of the original problem , and finally obtained by the vertexcut-set or cut vertex, which reduces the time complexity of the algorithm and improves the efficieney of the al-gorithm.
GUO Yuyan
Abstract: Operating system security has attracted the attention of researchers since the very beginning. Howto build a secure operating system has become a hot topic of current research, Based on trusted computing andactive host proteet. we designed and realized the system with kernel mode protection that provides functionssuch as ’Trusted boot, Process starts prolect, and Network access protect. Besides, it provides mandatory ac.cess control of critical resources.
WU Mingfen,QU Yunyun
Abstract: We make a thorough inquiry about the coneepts in diserete mathematics based on the amplifieationand minimum features of the closure. We collected some explicit concepts and implicit concepts of closurefrom discrete mathematics such as closures of binary relation ,strong part graph ,subspace sum subspace sgener.ating subgroup and so on, Trying to format the teaching of these concepts and procedure standardization in theframework of the closure, At the same time, we introduce our teaching programs and techniques. Finally, thethinking of relationship transitive closure is applied to the algorihm design of the shortest path and Euler roads.
JU Xingang,GOU Zhanfeng,SUN Hua
Abstract: In PWM digital dimming mode, the human eye Feeling to LED lighting brightness ( luminous fux)linear change is nonlinear. In order to make this nonlinear feeling has been corrected, luminous flux compen.sation is needed. Because a strict linear relationship exists between Luminous flux and pWM duty cycle,therefore, it will be done, according to the Luminous flux and the nonlinear characteristics of human eyebrightness feeling, to obtain nonlinear change PWM duty cycle of human eye linear brightness feeling. LUTand LPM of Quartus ll platform are used by the system, the data of duty cycle according to the nonlinear char-.ecteristics calculation are deposited to realize luminous flux compensation. As is shown in the test, the systemgets corect.
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