岩土工程技术

Development and Application of Measuring Automatic Deformation Monitoring System Based on Georobot TS30

Chen Lei, Yin Yanyun

2016, 30(3): 109-112,128. doi: 10.3969/j.issn.1007-2993.2016.03.001

[Abstract](65) [PDF 832KB](11)

Abstract:
In this paper,a kind of automatic deformation monitoring system is developed,which is based on the TS30,combined with GeoCOM technology,Visual C++ data base and data transmission technology.Accuracy statistics and inspection for traditional and automatic observation data is through internal accord accuracy,F hypothesis testing,and T hypothesis testing.By using case analysis,compared with the traditional method,the automatic deformation monitoring system has a great improvement in the time and accuracy of data acquisitions,which improves the operation efficiency of the field operation,and highlights the advantages and characteristics of automatic monitoring system in engineering application.This system will be used widely in deformation monitoring.

Shallow Marine Seismic Reflection Applied in the Investigation of Coral Island and Reef

Duan Zhigang, Liu Chengtian, Xia Lihua

2016, 30(3): 113-117. doi: 10.3969/j.issn.1007-2993.2016.03.002

[Abstract](43) [PDF 1909KB](6)

Abstract:
The coral reef is a special geotechnical type,its engineering characteristics is a new subject for the geotechnical engineer.There are fewer experiences in coral reef investigation,and no investigation code or norm exists at home.The borehole drilling is badly limited for the severe weather as well as the marine environment.Shallow marine seismic reflection is adopted in the investigation of a coral island in South China Sea,Combined with the borehole data,the seismic reflection figures out the geological stratigraphic sequence of coral clastic deposit and underlying reef limestone.The result achieved in depth mapping is quite satisfactory.It showes that the deposit interface in different reef phases is obvious,including of inner reef flat,atoll lagoon,seaward slope,offshore.Outer reef flat is somewhat unclear for the existence of hard modern beach rock.

Field Testing Study on Settlement and Stresses of Gravel Pile Composite Ground

Han Qiankun, Li Xiaojiang, Liu Junxin

2016, 30(3): 118-123,139. doi: 10.3969/j.issn.1007-2993.2016.03.003

[Abstract](98) [PDF 1690KB](14)

Abstract:
Design of Passenger Dedicated Line roadbed is on more reflected strict control on the embankment deformation.In the DK61 site of some railway line where soft clay foundation was used by gravel pile treatment,field monitoring of settlement and stress for composite ground was conducted on-stress variation,so data of settlement of embankment and foundation,soil pressure and pore water pressure have been obtained in the process of construction and after construction of the embankment.On the basis of the arrangement and analysis of the results in the field testing,the settlement of composite foundation during the construction and after construction of embankment,influence factors of settlement of composite ground under field construction conditions and settlement prediction rules has been studied,and it has statistically argued stress mechanism of soil pressure and pore water pressure.These research results provide useful information for theoretical research and engineering design in the further.

An Example of Consolidation in Large Area of Soft Clay

Han Shaoying, Zhao Zaili

2016, 30(3): 124-128. doi: 10.3969/j.issn.1007-2993.2016.03.004

[Abstract](40) [PDF 823KB](12)

Abstract:
The principle of preloading consolidation method is that the foundation soil under the load actions(with an increasing total stress σ) can increase pore water drainage(i.e.,reducing the pore water pressure μ) and effective pressure σ'.This paper introduces the design and construction methods to conduct drainage consolidation treatment to soft clay of large areas by combining the preloading with the plastic drainage plate with engineering examples.This paper also analyzes the engineering monitoring results and shows that after preloading consolidation treatment,the bearing capacity of the saturated soft clay foundation has been greatly improved,the soil consolidation effect is obvious within the depth range of the plastic drainage plate,the settlement after construction is also greatly reduced,and the primary consolidation degree of the foundation soil in all regions has been up to over 90%in a few years.

Research on the Algorithm of Architecture Data Extraction Based on Airborne LIDAR

Yan Liang, Xu Jiaohuang

2016, 30(3): 129-133. doi: 10.3969/j.issn.1007-2993.2016.03.005

[Abstract](29) [PDF 778KB](8)

Abstract:
Airborne laser radar measurement can quickly obtain the 3D information of high accuracy,which can be used in 3D city modeling.Construction is the main body of the city,and it has been a hot research topic in the construction of data extraction from airborne LIDAR data.Data extraction from airborne LIDAR data mainly includes the following steps:data preprocessing,building detection,roof reconstruction,boundary extraction,establishment of model and rule.In this paper,the research progress of this field is summarized,and the difficulties and developing direction of data extraction from airborne LIDAR data are described.

Inclined Bracing Deformation and Its Environmental Impact Control Measures

Du Ce

2016, 30(3): 134-139. doi: 10.3969/j.issn.1007-2993.2016.03.006

[Abstract](39) [PDF 1423KB](15)

Abstract:
Inclined bracing deformation has uniqueness,Using the model of beam on elastic to calculate deformation of retaining structure and the experience curve to predict the surface settlement is not safe.This paper by using finite element software PLaxis,Analyzing the characteristics of the foundation pit deformation using inclined bracing.Meanwhile,this paper proposes four methods to control the deformation of the pit.Through summarizing the large underground excavation,summed up the inclined bracing pit deformation behavior and deformation control measures.

Discussion of Different Hanging Shotcrete Applications Between Pile Foundation Pits

Xu Shixiong, Liu Xiangke, Hu Hongbiao

2016, 30(3): 140-142. doi: 10.3969/j.issn.1007-2993.2016.03.007

[Abstract](47) [PDF 662KB](11)

Abstract:
Three protective structure practice between retaining piles about building construction excavation structure are described on page 30,31 in the national Building Standard Design Atlas 11SG814.Several application examples are introduced to compare and analyze the problem of which is the best way.It is concluded that retaining structure design and construction should be selected according to the actual needs both economically feasible and economically reasonable approach,so that the cost savings and good yields effects will be realized to ensure the construction quality and safety conditions.

The Impact of Loess Sinkhole on the Highway Stability

Li Tao, Wei Zhanggang, Hu Yanyu

2016, 30(3): 143-147. doi: 10.3969/j.issn.1007-2993.2016.03.008

[Abstract](33) [PDF 4470KB](7)

Abstract:
The impact of loess sinkhole on the roadbed stability of loess areas is analyzed combined with the engineering examples,and treatment measures are proposed pertinently.

Application of Settlement Back Analysis in Oil Tanks Foundation Rectification

Wang Xiaobo, Liu Huancun, Deng Caixiong

2016, 30(3): 148-152. doi: 10.3969/j.issn.1007-2993.2016.03.009

[Abstract](21) [PDF 1967KB](6)

Abstract:
Based on a concrete engineering example of oil tanks,a mathematical model for settlement back-analysis is established in this paper by using the traditional layer-wise summation method and the principle of least square method.In the meanwhile,according to the strata subsidence deformation parameters obtained by the water filling test,a settlement back analysis related to the stratum parameters is carried out with the established mathematical model.Thus the equivalent modulus and compression modulus of stratum are calculated;the final subsidence and tilt rate of oil tank foundation are worked out as well.And the results can provide some references for the rectifying plans of oil tank foundation.For the proposed method in this paper,its principle is clear,the model is simple and the calculation is convenient,and it also has reference value and guidance for other similar projects.

FLAC^(3D) Analysis of the Soil Excavation Influence on the Deformation of Flexible Pressure Pipe

Zhang Qinxi, Shi Chaodong, Xu Chao

2016, 30(3): 153-157,163. doi: 10.3969/j.issn.1007-2993.2016.03.010

[Abstract](44) [PDF 1471KB](6)

Abstract:
In this paper,based on the theory of flexible pressure pipe structure,the stress state of the flexible pipe and the law of the joint action of the pipe and soil are analyzed by FLAG3" finite difference software.By orthogonal test,the influence of various factors on the displacement of the pipeline is given,and the significance level of the factors is given,which provides the basis for the design and research of the flexible pipe.

Research on Technical Measure for Metro Shieldtunnel Lateral Crossing Below Existing Railway Bridge

Yu Long

2016, 30(3): 158-163. doi: 10.3969/j.issn.1007-2993.2016.03.011

[Abstract](31) [PDF 1958KB](10)

Abstract:
In this paper,based on the actual case of metro shield lateral crossing below the existing railway bridge,the influence between the shield construction and the railway bridge was investigated.The regulations and provisions on the settlement of bridge in different codes were introduced.Move over,analysis was made on the settlement of the shield tunneling across the existing railway bridge by means of 3D FEM in two cases,which used and no used composite anchor pile reinforcement and the following technical countermeasures were proposed:firstly,pre-reinforcement was made for the ground surrounding the pile of the bridge where shield passing through,so as to improve the ground's stability and isolate protection of the bridge pile;secondly,strengthened segments with preserved grouting holes are adopted in the tunnel design;thirdly,the construction parameters should optimize,strengthen monitoring and reasonable information construction should be used.

2016 Vol. 30, No. 3