2019 Vol. 33, No. 1

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Technology Development and Exploration
Design of Geotechnical Amphibious Survey Platform
Hu Jianping, Li Xiaoji
2019, 33(1): 1-5,13. doi: 10.3969/j.issn.1007-2993.2019.01.001
[Abstract](50) [PDF 1522KB](16)
Abstract:
In the construction of seaports,bridges,wind power and other coastal projects,geotechnical investigations involve tidal flats or intertidal zones.These areas have characters of inundation at high tide,posure at low tide,loose soil and low bearing capacity,so that the survey platform can not be erected,the road can not be opened,The car and ship can not enter,giving survey and geotechnical testing difficulties.In summary,an amphibious platform with platform lifts,self-navigation,track walking and adaptive leveling is proposed.Operators use different purposes exploration equipment to complete exploration and sampling or a package of geotechnical test project to meet the needs of the basic design of modern water transport projects.The method created provides a useful reference for the integrated design of Chinese survey and equipment.
A Technique and Method for Dealing With Defects of Large Diameter Pile
Zhao Jianhua
2019, 33(1): 6-9. doi: 10.3969/j.issn.1007-2993.2019.01.002
[Abstract](65) [PDF 3888KB](15)
Abstract:
On the basis of a defect pile detected by two different methods before treatment,the property,position and size of the defect are analyzed and determined.According to the severity of the defect,ceutral hole extraction method is innovatively adopted.Concrete defects are treated with special machinery and artificial method in pile body,and concrete is poured after treatment.The results show that the defect treatment method is effective and can avoid the defects which can not be eradicated by using the traditional method such as grouting,thus this methed saves the time limit as well as the cost.
Research on Optimization of Treatment of Slopes With Interbreeding of Soft and Hard Rocks
Liu Jinyang, Xu Ce, Huang Wei
2019, 33(1): 10-13. doi: 10.3969/j.issn.1007-2993.2019.01.003
[Abstract](98) [PDF 2129KB](11)
Abstract:
In view of optimization of treatment of slopes with interbreeding of soft and hard rocks,there are problems of scheme preference and objectiveinformation.And based on cosine decision principle,the cosine decision method has been established for optimization of slopes treatment scheme with interbreeding of soft and hard rocks.First of all,this method divides the evaluation index into 5 levels,and the weight of index is determined according to its level.And then according to the cosine formula,calculated the cosine of the angle between the index line of evaluation scheme and ideal target line segment,and building a model of optimization of treatment of slopes with interbreeding of soft and hard rocks.The model is applied to the optimization of Pengjiawan slope control scheme and the optimal treatment scheme is obtained,thus it provides the basis for its treactment design and construction decisions.
Key Points for Geotechnical Investigation of Site Formation in Beijing
Li Li, Hou Dongli
2019, 33(1): 14-17,21. doi: 10.3969/j.issn.1007-2993.2019.01.004
[Abstract](70) [PDF 1009KB](9)
Abstract:
Site formation is a new thing,and the relevant codes are extremely limited about site formation engineering,which leads to no basis for site formation investigation.On the basis of engineering investigation of Beijing several site formation projects,through summarizing the geotechnical engineering problems in the site formation work,this article puts forward some suggestions and requirements on site investigation,and expected to provide some technical supports to related site formation work.
Typical Problems Analysis of Geotechnical Engineering in an Airport in Southern Xinjiang
An Haitang, Liu Ping
2019, 33(1): 18-21. doi: 10.3969/j.issn.1007-2993.2019.01.005
[Abstract](69) [PDF 817KB](13)
Abstract:
The proposed siteis located in the Aksu area in southern Xinjiang,which is the Kuche River alluvial plain.The terrain is relatively flat.The construction projects include airport runways,terminal buildings,office buildings and ancillary buildings.In addition to conventional drilling during the survey,the geotechnical characteristics and the bad soil were tested and analyzed by pumping test,on-siteimmersion load test and SPT.Though Groundwater,sand liquefaction,corrosive and saline soil were analyzed.It was summarized the problems that should be paid attention to when conducting geotechnical investigations in desert arid areas.
Experimental Research
Research on Technique and Experiment of Multi-pipe Synchronous Grouting and Water-blocking in Large Particle Gravel Strata
Ma Qingxun, Luan Jingjing, Zhang Youxiang
2019, 33(1): 22-27. doi: 10.3969/j.issn.1007-2993.2019.01.006
[Abstract](80) [PDF 8061KB](11)
Abstract:
The large influence radius and the high permeability coefficient are the characteristics of large particle gravel strata which holds abundant groundwater.Using the method of precipitation to control the groundwater will cause serious waste of water resources.The sealing curtain techniques are fewly applicable to the large particle gravel strata.In addition,different water-blocking schemes have great influence on the construction period and cost.By taking an example of deep foundation pit in Beijing as the analysis condition,this paper puts forward a scheme with multi-pipe synchronous grouting and water-blocking for deep foundation pits.By carrying out grouting model tests in the engineering site,some key technical indexes,such as the construction technology,grouting material and construction parameters,are systematically studied of multi-pipe synchronous grouting.By field measurement and laboratory analysis,this paper makes the following conclusions:When the grouting diffusion radius is greater than 0.5 m and the permeability coefficient of grout is greater than 5.2×10—6 cm/s,by using the method of synchronous sleeve valve tube grouting in large particle gravel strata,the permeability of gravel stratum will be decreased;The drainage of the foundation pit will be greatly reduced simultaneously.So this reliable water-blocking technique can provide reference for the groundwater control design and construction of similar foundation pit engineering in deep foundation pit.
Thermal Response Tests and Suitability Assessment of Vertical Buried Pipe
Tong Xin, Liu Yuan, Yan Bo
2019, 33(1): 28-31. doi: 10.3969/j.issn.1007-2993.2019.01.007
[Abstract](53) [PDF 923KB](13)
Abstract:
Taking the ground source heat pump engineering project in Wuhan as an example,the thermal response tests were carried out of double U type vertical buried pipe using two methods for analysis and comparison,which were constant heatflux method and constant temperature method separately.There were two boreholes(R1、R2).R1 was tested by the constant heat-flux method,and the heat fluxes are 6 kW and 3 kW.R2 was tested by the constant temperature method,and the inlet temperature are 30℃ and 35℃.We discussed and analyzed the result of the tests based on introducing the geological condition of the project、the principle and design of the test.Combined with the hydro-geological conditions and drillability of rock and soil,we analyzed the suitability of vertical buried pipe ground-source heat pump system in this area and the study could provide useful references for the optimum design.
Experimental Study on the First Layer of Sands in Shijiazhuang City
Duan yongle, Qin yanting, Li nahui
2019, 33(1): 32-35. doi: 10.3969/j.issn.1007-2993.2019.01.008
[Abstract](66) [PDF 783KB](9)
Abstract:
As the bulk material,sand is not easy to take the original sample,take the sample high cost,take the sample difficulty and so on,and lack the relevant laboratory test experience.In this paper,the physical properties and shear strength indexes of sand are studied by water content test,density test,particle analysis(sieve analysis)test,repose angle test and direct shear test(quick shear),and the corresponding fitting equations and suggestions are put forward.
Laboratory Study on Strength Characteristics of Expansive Mudstone
Wang Tao, Cao Xueshan, Zhang Rongkuan
2019, 33(1): 36-39. doi: 10.3969/j.issn.1007-2993.2019.01.009
[Abstract](73) [PDF 1643KB](6)
Abstract:
The strength variation of expansive mudstone remolded samples was studied by indoor tests after water swelling under different initial states and pressures.The research results show that the cohesion of remolded expansive mudstone increases firstly and then decreases with the raising of moisture content.The cohesive force will peak when the moisture content is about 18% after water absorption saturation.The cohesion and the internal friction angle of the remolded expansive mudstone increase with the raising of overlying pressure,and their relationship approximately follows a power function.
The Comprehensive Analysis of the Soil Test Results in Beijing Area
Han Sujun
2019, 33(1): 40-45,48. doi: 10.3969/j.issn.1007-2993.2019.01.010
[Abstract](67) [PDF 1716KB](19)
Abstract:
Through the comprehensive analysis of the physical indexes and the mechanical indexes used in the soil test results of all kinds of soils in Beijing area,some relationship diagrams are drawn between the indexes of physical property and the indexes of mechanical property based on the data statistics,regression analysis and empirical correction.Then,some regular cognitions and conclusion are summarized.Taking advantage of the regulations and conclusions,we can make correct analysis and judgment to some abnormal phenomena in the soil tests,offered the more rational and more accurate test data for the geotechnical engineering survey and design,in order to assure the quality and safety of the engineering construction.
Analysis of Building Foundation Detection Technology and Method
Huang Dongliang
2019, 33(1): 46-48. doi: 10.3969/j.issn.1007-2993.2019.01.011
[Abstract](60) [PDF 640KB](13)
Abstract:
In this paper,the detection of building foundation is taken as the research object,starting from the analysis of foundation and its detection meaning,and the analysis of foundation detection technology,more detailed analysis and elaboration are carried out around this central issue,and the important significance of foundation detection is expounded in ensuring the stability and reliability of engineering building structure.
Deep Foundation Pit Technology
Frost Heaving Deformation Numerical Analysis of Deep Foundation Pit Support System
Li Chuang, Liu Xiaobing, Liu Wenjie, Liang Wen
2019, 33(1): 49-54. doi: 10.3969/j.issn.1007-2993.2019.01.012
[Abstract](58) [PDF 1227KB](9)
Abstract:
The foundation pit works may experience winter in the seasonal frozen soil area,and its supporting structure will be affected by the frost heaving of the soil.In this paper,the deformation problem is studied of deep foundation pit supporting structure caused by soil frost heave.Firstly,based on the frost heaving theory,the influence mechanism of soil frost heave is analyzed on the foundation pit supporting structure.Then,the basic equations of temperature field and stress field of soil are constructed,based on specific engineering example and the relevant thermal parameters and mechanical parameters of finite analysis are defined.Finally,the ANSYS finite element analysis software was used to simulate the temperature change,the axial force change of the anchor and the horizontal displacement of the pile.The simulation results are basically consistent with the practical monitoring results,and good simulation results have been obtained,which provides a reference for the subsequent wintering projects like deep foundation pits.
Analysis on the Model of Double-row Piles for Deep Excavation
Wang Jie, Han Lei, Xu Yunfeng
2019, 33(1): 55-58. doi: 10.3969/j.issn.1007-2993.2019.01.013
[Abstract](77) [PDF 740KB](16)
Abstract:
An improved calculation model of double-row piles is submitted.Based on the case of “Excavation Engineering Handbook”,the rationality of theimproved calculation model was verified by compared with the 2D finite element model.The behavior of double-row piles is also analyzed.Through further parameter analysis and comparativeanalyse with calculative result of finiteelement model,the influence of the stiffness of the soil and the distance of two piles on calculation results are studied.The results show that the improved calculation model is suitable for the design and calculation of double-row pile engineering.
Design and Practice of Foundation Pit Engineering in a Contaminated Site in Shanghai
Liu Yunzhong
2019, 33(1): 59-62. doi: 10.3969/j.issn.1007-2993.2019.01.014
[Abstract](79) [PDF 935KB](20)
Abstract:
The restoration of contaminated soil assisted the site excavation is netded by a chernieou contaminated site in a planned development area in shanghai.According to the spatial distribution characteristics of pollution sites,the surrounding environment and the volatility of pollutants,Through the rational selection of foundation pit protection scheme,excavation design of the area is divided into different working conditions,the excavation made is designed of closed greenhouse grading excavation,and the partial use of gravity type cement soil retaining wall combined steel sheet pile and other composite enclosing plan.The remediations of contaminated sites have been quick,efficient,cheap,safe and satisfies environmental protection requirements.It has accumulated rich experience for similar projects.

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