岩土工程技术

Software Development of Automatic Drawing Tool for Groundwater Monitoring Well Comprehensive Histogram

Zhou Yang

2020, 34(3): 125-129,154. doi: 10.3969/j.issn.1007-2993.2020.03.001

[Abstract](93) [PDF 4382KB](23)

Abstract:
In order to improve the efficiency of drawing groundwater monitoring well comprehensive histogram, a drawing tool is developed based on Excel and AutoCAD. This drawing tool is composed of three parts, namely data storage module, drawing module and drawing program. Excel is the secondary development platform and data storage module. AutoCAD is the graphics drawing module. Drawing program written by VBA language is the data processing module. Data classification input design of monitoring wells in Excel drawing workbook is helpful for structured data entry and data checking. The partition design of AutoCAD drawing template makes drawing normalization. By using this drawing tool, automatic and standardized drawing of groundwater monitoring well comprehensive histogram could be realized.

BOTDR Monitoring Analysis of Loose Layer Deformation Compression of a Shallow Area in Tongzhou, Beijing

Li Chao, Xiao Jingze, He Jing, Cai Xiangmin, Liu Yu

2020, 34(3): 130-134. doi: 10.3969/j.issn.1007-2993.2020.03.002

[Abstract](58) [PDF 4270KB](13)

Abstract:
The compression deformation of the loose layer is the main factor causing the land subsidence, and large deformation will cause a series of geological disasters. In order to carry out fine observation on the compression deformation of loose layer in Tongzhou, Beijing, 112 m thick loose layer has been monitored for one and a half years by using directly buried cable. The results show that during the monitoring period, the main compressed layer of the loose layer in the monitoring area is 5~30 m. The amount of compression in this layer tends to decrease with time, and also decrease with depth. Based on the analysis, the main causes of the compression deformation of the loose layer in this area are the change of groundwater level, the additional load of construction and the characteristics of its own lithology. BOTDR technology can accurately obtain the deformation information of loose layer, and it is an effective means to monitor the compression of loose layer.

Application of Full Casing Full Rotation in Reinforcement Engineering of a Riprap Silt Stratum

Zhang Qinxi, Yan Jinbo, He Shiming

2020, 34(3): 135-139. doi: 10.3969/j.issn.1007-2993.2020.03.003

[Abstract](53) [PDF 16978KB](13)

Abstract:
In the construction of existing building reinforcement piles in riprap silt strata, the conventional construction methods of rotary drilling, spiral digging and impact holing with slurry supporting are limited. The impact of vibrations on sensitive buildings generated by drilling cannot be ignored. In order to minimize the disturbance to existing buildings and soil layers, it is necessary to adopt a process with little interference to ensure the safety of existing buildings. Due to the flexible technology and high degree of mechanization of the full casing full rotation, combining with advantages of safe, reliability, small disturbance to the surrounding, high vertical precision of the hole and no mud pollution, this technology has been widely used in the pile foundation construction of adjacent existing buildings. The application of the full casing full rotation in the reinforcement of a project in Dalian is introduced. Focusing on the characteristics of no hole collapse and no mud during drilling, in order to improve the bearing capacity of the pile foundation and the quality of the pile body, gas lift reverse circulation and pump lift reverse cycle are applied, achieving strict sediment control requirements. It provides reference and experience for similar construction of rock-socketed pile foundation.

A Method for Optimized Triangulation Based on Unmanned Aerial Vehicle Photogrammetry in Simple Geomorphology

Fan Penghao, Jiang Quan, Yin Yanyun

2020, 34(3): 140-142. doi: 10.3969/j.issn.1007-2993.2020.03.004

[Abstract](57) [PDF 7397KB](16)

Abstract:
Unmanned aerial vehicle (UAV) is used to take photogrammetry in a simple geomorphology area,and the photos are calculated by professional triangulation software.The unqualified triangulation result is solved by take redundant multi-scale aerial images and calculated by combined triangulation once more.The three-dimensional(3D) model’s accuracy is improved to meet the accuracy requirements in large-scale topographic mapping using UVA photogrammetry model.

Application of Three Constitutive Models of Soil Based on Midas GTS NX

Chi Hengtian, Wu Zhenyu, Liu Xiaozhi

2020, 34(3): 143-149. doi: 10.3969/j.issn.1007-2993.2020.03.005

[Abstract](350) [PDF 6850KB](63)

Abstract:
Finite element software is an important means for engineers to analyze the foundation pit in sensitive environment by numerical simulation, and the key of numerical simulation is to select appropriate constitutive model. In order to understand the suitability of three soil constitutive models commonly used in engineering, the excavation process of a large deep foundation pit is simulated by using Midas GTS NX three-dimensional finite element software. The numerical simulation results of different constitutive models are compared with the monitoring results of foundation pit, and then the applicability of the constitutive model is analyzed. It can be used as a reference for similar projects in this area in finite element numerical simulation analysis.

Application of Electromagnetic Wave CT in Karst Detection for Main Bearing Platform of Chishui River Bridge

Chen Chuan

2020, 34(3): 150-154. doi: 10.3969/j.issn.1007-2993.2020.03.006

[Abstract](73) [PDF 9681KB](13)

Abstract:
Electromagnetic wave CT is widely used in the detection of carbonate karst cave, but it is often affected by the geological conditions of the work area and the site construction conditions, causing anomalous artifacts that are difficult to explain. The forward model is applied to the processing and interpretation of the rock mass under the main bearing platform of Chishui River Bridge through the discussion and the establishment of the forward model. The effect of the pile foundation abnormal body on the measurement results is solved. Combining with the characteristics of construction site, the detection results are divided into surface effect anomaly area, well wall response anomaly area, pile foundation and surrounding rock comprehensive response anomaly area, complete surrounding rock area, and good application effect has been obtained.

Stability Analysis of H1 Landslide on Baoshan Highway in Yulong County, Yunnan Province

Li Hongjun

2020, 34(3): 155-157,162. doi: 10.3969/j.issn.1007-2993.2020.03.007

[Abstract](54) [PDF 1947KB](18)

Abstract:
Yunnan is located in the northeastern boundary of the India-Eurasia collision zone. The long-term relative movement of the two plates has caused frequent geological disasters in Yunnan Province. The landslide deformation characteristics were analyzed by the basic characteristics, landslide structure and topography, as well as geomorphology conditions of the Baoshan Highway landslide in Lijiang. The stability of the landslide under different working conditions was calculated and analyzed.

Application of Composite Grouting in Anti-seepage of Deep and Thick Pebble Stratum

Li Rantong, Cai Guanjun, Li Jiukun

2020, 34(3): 158-162. doi: 10.3969/j.issn.1007-2993.2020.03.008

[Abstract](49) [PDF 20399KB](19)

Abstract:
In the study of anti-seepage in deep foundation pit of deep and thick pebble stratum, focusing on the geological characteristics of pebble stratum with high permeability, new idea and specific test process of anti-seepage in foundation pit are introduced. Through the analysis of groundwater monitoring results, it proves the rationality of this technology, and the experience obtained has certain reference significance for similar projects.

Stability Analysis of a High Fill Slope in Investigation

Liu Zhongqian, Liu Yan

2020, 34(3): 163-166,177. doi: 10.3969/j.issn.1007-2993.2020.03.009

[Abstract](134) [PDF 5607KB](26)

Abstract:
When new buildings are built on the high fill slope in mountain area, it is necessary to take the overall stability of the slope as the premise, and select a suitable and reliable foundation form at the same time. Based on a practical case of high fill slope, according to the characteristics of the proposed building and slope, different slope stability analysis methods are used to calculate and analyze the slope in the investigation. The proposed building plans to adopt large-diameter rock socketed pile foundation combined with slope protection structure to jointly ensure the safety and stability of the building.

Key Technologies in Construction of Collapse Regulation Project for Cliff-type Dangerous Rock Groups

Zhang Luming, Zhou Yong, He Min, Wang Shouzhi

2020, 34(3): 167-173. doi: 10.3969/j.issn.1007-2993.2020.03.010

[Abstract](46) [PDF 13656KB](20)

Abstract:
Aiming at the problems of difficulty and high risk in the construction of landslide remediation project of Lianghekou Hydropower Station in Baoxing County after Lushan M7.0 strong earthquake,a set of key technologies for construction of cliff-type dangerous rock mass group are put forward, including cantilever scaffolding design, overhead cableway transportation design and hole grouting construction of fractured rock mass. The complete set of technology enables the timely renovation of dangerous rock mass on steep cliffs, wins precious time for post-disaster reconstruction, saves costs, and effectively protects the fragile ecological environment in earthquake-stricken areas. It also further enriches the theory and practice of prevention and control of dangerous rock mass, and provides a new way of construction and environmental protection for similar projects.

Influence of the Chemical Improvement on the Compaction Characteristics of the Bayer-process Red Mud

Li Bin, Sun Zhaoyun, Yang Weigang, Han Zhaoyou, Yan Xiangpeng

2020, 34(3): 174-177. doi: 10.3969/j.issn.1007-2993.2020.03.011

[Abstract](49) [PDF 794KB](8)

Abstract:
Bayer-process red mud has special physical and hydraulic properties, can be used for subgrade filling through improved treatment. Lime,cement,phosphogypsum and composite modified materials are selected for chemical improvement of red mud, and the effect of different modified materials on the compaction characteristics of red mud is analyzed. The results shows that different materials have different characteristics in improving red mud compaction, and the optimum moisture content and maximum dry density of red mud improved by each material show different increasing and decreasing trends with the change of dosage. It provides a reference for the selection of improvement methods and engineering application of Bayer red mud.

Test Method for Physical Strength of Cement-soil Pixing Piles

Liu Huaqiang, Huang Genmin, Cai Yiping, Cai Lei

2020, 34(3): 178-180,187. doi: 10.3969/j.issn.1007-2993.2020.03.012

[Abstract](71) [PDF 6461KB](18)

Abstract:
The specific problem of physical strength testing of cement-soil mixing piles is discussed. It is pointed out that the physical quality test of the compressive strength of cement-soil mixing piles and the strength test of indoor cubic standard specimens are not uniform. The strength relationship between specimens of different sizes is unclear and lacks the basis for use. The relationship between the unconfined compressive strength of cement-soil with different sizes and shapes is analyzed through experimental research. It is feasibe to directly evaluate the strength using the test results with cylindrical core samples, and the key issues need attention during the process of obtaining core samples is pointed out also, all of which discussed maybe contribute practical and guiding significance.

Research and Application of Testing Theory of Pile Foundation Test Pile in a Power Plant

Meng Xianzhong

2020, 34(3): 181-187. doi: 10.3969/j.issn.1007-2993.2020.03.013

[Abstract](76) [PDF 2781KB](19)

Abstract:
Combined with the pre-construction geological conditions of the pile foundation of China Resources Power Plant (Bohai New Area), the economic and technical comprehensive comparison of the foundation plan was carried out through careful analysis, research and evaluation of the prototype test. The distribution law of the side resistance of the pile was analyzed, which could provide reasonable pile foundation bearing capacity, construction technology and construction parameters in the actual project. This research could provide guidance for construction of pile foundation, and also provide recommendation for the engineering detection and construction supervision.

2020 Vol. 34, No. 3