岩土工程技术

An Evaluation Model of Supporting Schemes for Slope with Triangular Fuzzy Numbers and Its Application

Wang Guofu, Wang Weiming, Feng Yuguo

2011, 25(4): 163-167,172. doi: 10.3969/j.issn.1007-2993.2011.04.001

[Abstract](41) [PDF 532KB](4)

Abstract:
Due to inadequate information,incomplete data in evaluation of supporting schemes for slope,and the complicacy and uncertainty of the evaluation for slope and the fuzziness of human thinking,the evaluation value of the scheme is difficult to be expressed, the value represented in triangular fuzzy number is more reasonable. In order to solve the optimization of supporting schemes for slope with triangular fuzzy numbers,a comprehensive evaluation model based on triangular fuzzy numbers of connection numbers of set pair analysis is proposed. First the triangular fuzzy numbers are transformed into connection numbers by using the median, and the interval of value prescribed by supremum and infimum of the triangular fuzzy numbers, depend on the connection numbers theory of set pair analysis; then, the decision-making model of connection numbers is established based on the definition of addition and multiplication of connection number,and the optimum schemes can be obtained by the comprehensive decision values. The median and the supremum and infimum of the triangular fuzzy numbers are used in this model; it is more objective and reasonable. A practical example indicates the method is simple and credible.

Time-varying Creep Constitutive Model Identification of Rock Based on HPSO Algorithm

Liu Wenbin

2011, 25(4): 168-172. doi: 10.3969/j.issn.1007-2993.2011.04.002

[Abstract](38) [PDF 516KB](5)

Abstract:
Hybrid Particle swarm optimization (HPSO) algorithm is a stochastic global optimization technique with many advantages, such as quick convergence, simple regulation and easy implementation. In order to determine the time-varying parameters of creep constitutive model of rock, in this article, a new method is presented using HPSO algorithm and fish language, which was contained in FLAC. At first, the stochastic values of parameters are initialized and the difference between the value computed and the datum measured during creep was regarded as fitness function to evaluate quality of the parameters. Then the parameters are updated continually using HPSO until the optimal parameters are found. Thus time-varying parameters of creep constitutive model of rock are identified adaptively during computation. Simulations was done for shale creep experiment, the results show that hybrid particle swarm optimization algorithm is effective in identifying the time-varying parameters of creep constitutive model of rock and viscoelastic characteristics of shale can be described better by using inconstant creep constitutive model.

Analysis of Pile-anchor System With Fulcrum Method and Parameter Backcalculation Based on Monitorint

Zhang Chaowen, Ji Xiaopeng

2011, 25(4): 173-179. doi: 10.3969/j.issn.1007-2993.2011.04.003

[Abstract](33) [PDF 639KB](6)

Abstract:
Deformation as a control condition for supporting structure design in foundation pit is a very complex engineering problem, but fulcrum method is accepted by lots of engineers for its clear computing model and simple procedure. In fulcrum method calculation, the accuracy of the m-value effects the displacement and internal force results of supporting structure directly, so,this paper put the fulcrum method modeling inversion analysis used in actual project, in excavation process consides supporting deformation nonlinear. It develops FORTRAN program executing inversion calculating for supporting structure. getting m-value through inversion analysis and forecasting the deformation of supporting structure, realizing dynamic design and information construction.The results show that deformation inversion analysis obtains good results during parameter inversion and displacement prediction of deep foundation pit engineering, proving that the method is reasonable on inversion analysis and prediction during deep foundation pit excavation.

Analysis on Several Main Points in Urban Road Non-destructive Inspection of Ground Penetrating Radar

Su Zhaofeng, Chen Changyan, Zhang Hui

2011, 25(4): 180-182,186. doi: 10.3969/j.issn.1007-2993.2011.04.004

[Abstract](34) [PDF 1193KB](8)

Abstract:
According to the concrete problems of GPR in detecting city roads, the article introduces severa.l technical points of GPR such as central frequency of antenna,laying the measuring line,the measuring line location, testing speed,electromagnetic wave velocity and so on。It is important to access the "first hand" effective information of the target in degree。The article analyses all kinds of factors influence degree to the detecting effect in particular。Thorough practical project,selecting the suitable central frequency of antenna and the best combined parameter can guide the road detecting effectively。The detecting conclusion provides the scientific evidence to repair the road reasonably。

Oceanographic Engineering Investion Attemption and Exploartion

Liu Yuehui, Zhou Shichong, Li Pulin

2011, 25(4): 183-186. doi: 10.3969/j.issn.1007-2993.2011.04.005

[Abstract](35) [PDF 658KB](7)

Abstract:
For obtain the geological datum of Oceanographic engineering, we used the methods of areal geology datum collection, physics exploration, engineering drilling and Soil Test.Through Investingation of petroleum platform and offshore pipeline route in east bay of Liao Ning,we got some experience of the investiongation, and also made a good effect. The article briefly inrtoduced the investiongation meothds and contents, meanwhile explaind contents of the analysis and given evaluation about the areal geoloagy,the site of offshore pipeline route, the project of platform mudmat and the steel cannular pile.Through the investingation attemption of oceanographic engineering we also discoverd some existing problems in domain of the oceanographic engineering investingation at present.

Understanding of the Recently Deposited Soil in Beijing Area

Ma Yujie

2011, 25(4): 187-191. doi: 10.3969/j.issn.1007-2993.2011.04.006

[Abstract](67) [PDF 622KB](9)

Abstract:
The recently deposited soil was recognized in 1950s. But now in engineering practice there're still some difficulties in distinguishing recently deposited soil. In order to know this kind of soil better and instructing the work of geotechnical investigation more effectively, summarization of other researchers' knowledge and experiences was combined with the author's practical analysis. Based on these, the basic characteristics and distribution of recently deposited soil in Beijing area were expounded firstly. Then the engineering geological characteristics such as physical and mechanical properties and foundation carrying capacity were discussed. Finally, the discriminances about recently deposited soil were concluded.

Application of Shallow Foundation in Hunan Shaoyang of a High-rise Building

Xia Xiangqing, Yang Tianchun, Wang Shidang

2011, 25(4): 192-194,198. doi: 10.3969/j.issn.1007-2993.2011.04.007

[Abstract](48) [PDF 640KB](10)

Abstract:
The authors mainly introduce the application of shallow foundation in Shaoyang of a high-rise building in this paper, and emphasize the importance of elaborately investigate in overburden when in high-rise buildings, and also point out the feasibility of shallow foundation in some high-rise buildings at certain geological conditions. According to the results of soil test and in-situ test, the bearing capacity and deformation of the soil have been analyzed. At the same time, the authors reveal the hydrogeology conditions, and put forward two foundation projects. At last, the shallow foundation has been adopted basing on factors of construction, economy, safety and environment. The largest settlement is only 5.0mm and the average value is 3.4mm, which is far less than the national standard limits, after the project having been completed. In addition, this scheme save cost about 800 thousand yuan and shorten the construction period about 2 months comparing with the traditional rock-socketed pile foundation. So, the shallow foundation can be adopted in high-rise buildings at certain geological conditions, it can save cost and shorten the construction period.

The Influence of the Building on Ground Settlement Caused by Excavation of Shallow Tunnel

Xu Yingzi, Gao Wei, Song Fengchao

2011, 25(4): 195-198. doi: 10.3969/j.issn.1007-2993.2011.04.008

[Abstract](42) [PDF 682KB](6)

Abstract:
By using analytical method, the excavation induced ground ground settlement is analyzed. Through surface subsidence Caused by rock-soil excavation and the the relative subsidence caused by distributed load on semi-infinite plane,the ground settlement formular caused by the shallow tunnel excavation across the surface buildings. Through examples given, the feasibility of this method is proved. By using the following method, the influence of the weight of the buildings and the position relations between shallow tunnel and building on ground settlement are analyzed.The results of the study indicate that:The ground settlement caused by the shallow tunnel excavation is increased with the increase of building's weight; the distance of building center to tunnel axis is one of the important factors, that influence of the existing building on ground settlement is negligible when ground building is over a certain range of distance. The research results can provide certain reference for existing similar tunnel engineering.

A Research on Test Specimen for Multi-stage Loading Triaxial Which is Undrained Because of Lithification

Chen Chunfang, Chen Xiuyun, Lou Xihua

2011, 25(4): 199-203,210. doi: 10.3969/j.issn.1007-2993.2011.04.009

[Abstract](43) [PDF 715KB](4)

Abstract:
After the research on the contrast test between hundreds of groups of on soft clays test with a specimen for Multi-stage loading Triaxial which is undrained because of lithification and many normal specimens test (briefly called Diversely cut) from Ningbo and Wenzhou,it shows that there are great difference on cutting sliding surface soft clay,while Diversely cut can be replaced on no-cutting sliding surface soft clay after master the test experience and test skills.

Research on the Type of Geo-Hazard, Distribution and Evolutionary Characteristics in Liu Ba County

Qi Purong, Chen Haijuan

2011, 25(4): 204-206. doi: 10.3969/j.issn.1007-2993.2011.04.010

[Abstract](33) [PDF 583KB](5)

Abstract:
Based on the detailed geo-hazard survey in Liuba county, there were ahogether 239 geo-hazard cases. The primarily type of geo-hazard are landslide and collapse, accounting for 98.33%. The geo-hazard scale by small primarily, altogether has 190, accounts for 79. 50% of the total geo-hazard cases. Has studied the distribution of region, villages and towns, time in Liuba County. The geo-hazard evolutionary characteristics and formation factors are analyzed.

The Design and Development of the Transportation Geotechnical Engineering Geographic Information System of Jiangxi Province

Ji Qiwei

2011, 25(4): 207-210. doi: 10.3969/j.issn.1007-2993.2011.04.011

[Abstract](23) [PDF 666KB](4)

Abstract:
the transportation geotechnical engineering geographic information system is playing the vital role in the national economy and in the Transportation engineering construction. The application of GIS and computer technology in building the transportation geotechnical engineering geographic information system has been the focus as well as frontier of transportation in terms of foreign or domestic in recent years. In this paper, the transportation geotechnical engineering geographic information system using component GIS and computer technology, from the perspectives of design of the system software and hardware, overall structure, application functions and so on; discussed the design and development of the transportation geotechnical engineering geographic information system of Jiangxi province.

Deposition Test Research on Sand and Stone in Simulated Shaft

Liu Xinliang, Yin Xiaoli, Li Yanxia

2011, 25(4): 211-213. doi: 10.3969/j.issn.1007-2993.2011.04.012

[Abstract](41) [PDF 658KB](3)

Abstract:
During the process of sand and stone backfilling, such abnormal phenomena like instable backfilling height, large extent of the simulated casing stress, which directly affect the safety of project. By preliminary analysis, the behavior of sand and stone when backfilling is the major factor that leads to instable backfilling height and large extent of the simulated casing stress. Using simulated shaft for sand and stone deposition experiments, the results show that the fine particle is one of the prime reasons leading to instable backfilling height. and the strain of the simulated casing increased abruptly to one time greater than before in the process of the "abrupt deposition".

Analysis on the Impact of Fibers on the Property of Expansive Soil Reinforced with Lime

Li Zhipeng, Zhang Yuting, Ma Xilei

2011, 25(4): 214-217. doi: 10.3969/j.issn.1007-2993.2011.04.013

[Abstract](21) [PDF 657KB](3)

Abstract:
The researcher first did experimental analysis on the basic property of expansive soil, and the compaction test on natural expansive soil and on lime soil with and without fibers. The conclusion is that the lime soil with a small quantity of fibers has little effect on optimum moisture content and the maximum dry density. According to the linear swelling ratio experiment, the researcher concludes that fibers can retain the expansion of the lime. The linear expansion rate decreases remarkably with the increasing of the mixing amount of fibers between 0.05%-0.1%, but slightly between 0.1%-0.2%. With the unconfined compaction test and CBR (California Bearing Ratio), fibers which are reinforced can increase the compressive press of the lime, and the practicability of the above method is evaluated in this paper.

2011 Vol. 25, No. 4