2015 Vol. 29, No. 2

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Development and Creation
Application of AutoLISP in Engineering Computing
Wang Xiaobo, Hou Yingjie
2015, 29(2): 55-58,64. doi: 10.3969/j.issn.1007-2993.2015.02.001
[Abstract](28) [PDF 1105KB](9)
Abstract:
Three-dimensional solid reconstruction is the technological basis of engineering planning, design and management. By using AutoLISP programming method and employing the interpolation theories with inverse distance weighted method and Delaunay triangulation method, a program is developed for engineering data processing. This program can carry out a discrete point data interpolation, three-dimensional digital terrain model generation, three-dimensional solid reconstruction and engineering earthwork calculation. With the proposed method, the program has strong interoperability, easy and visual operability, wide applicability, and high accuracy. At the same time, the program can greatly reduce the working strength of engineers and improve the work efficiency. And furthermore, the application of this program is not only beneficial to the designers to estimate and utilize the results in engineering calculations, and is helpful for designers to make a timely design adjustment, so as to optimize the engineering design and reduce the proiect costs.
Contributions to the Source of Groundwater Nitrogen Pollution in Hun River Riparian Zone
Liu Liya, He Jiangtao, Wang Junjie
2015, 29(2): 59-64. doi: 10.3969/j.issn.1007-2993.2015.02.002
[Abstract](44) [PDF 1499KB](8)
Abstract:
Focused on the nitrogen pollution of the groundwater and river and ground surface of Shenyang Hun river water source area, Hydrus -1D was used to obtain the water volume and nitrogen concentrations at the bottom of the unsaturated zone, which can be considered to represent the regional results as initial values of the aquifer model built by Visual Modflow, which was used to simulate the nitrogen migration and transformation, and these can combine the simulation in top soil, unsaturated zone and aquifer together. In addition, compared with the groundwater sampling test results, the simulating and calculating results mentioned above were used to calculate the contribution rates of various groundwater nitrogen pollution sources by equilibrium formulas. The conclusions suggested that ammonia nitrogen in the southeast part was mainly from Hun River, and the contribution rate was 61.79%;Nitrate nitrogen in the northwest part was mainly from top soil vertical infiltration, and the contribution rate was 43. 92%.
Technology Probe and Research
Research on Cement & Plaster Similar Materials Proportioning Test
Xiao Jie, Liu Baoguo
2015, 29(2): 65-68,108. doi: 10.3969/j.issn.1007-2993.2015.02.003
[Abstract](40) [PDF 855KB](7)
Abstract:
The sand-cement ratio, the ratio of cement to gypsum and barite percentage of the total aggregate were selected as three factors, and every factor had five variable levels. According to twenty five schemes of material mixture ratio designed by orthogonal design method, shape volume testing, weighing, moisture content rate test, laboratory uniaxial compression test and split test were conducted. The tests results show that physical and mechanical indexes of similar material vary in a large range and can meet the needs for rock similar material in different physical model test of rock slope. Write a procedure for regression analysis based on MATLAB. Set the sand-cement ratio as X1, the ratio of cement to gypsum as X2, barite percentage of the total aggregate as X3, density indicators as Y1, compressive strength indicators as Y2, tensile strength indicators as Y3. Do regression analysis for the relationship between X1,X2,X3 and Y1,Y2,Y3 by using the procedure, and obtained the empirical formula of the cement & plaster similar material density, compressive strength and tensile strength. We can calculate the material ratio by physical and mechanical indicators of similar material with the empirical equation based on the mix design.
Analysis on All-digital Mapping Method in Multi-factor Measurements of Topographic Maps
Jia Gao, Chang Jian, Ma Qiang
2015, 29(2): 69-72. doi: 10.3969/j.issn.1007-2993.2015.02.004
[Abstract](32) [PDF 823KB](7)
Abstract:
The all-digital mapping has high precision, fast speed, inside and outside the industry of the integration advantage. With the development of GPS and GIS technology, it has been developed and applied rapidly in recent years. In the multi factor topographic survey, the advantages of all-digital mapping has been fully exploited. In this paper, combined with the large scale a unit research area topographic mapping example introduces several measurement methods of the practical application, and provide reference for similar engineering.
Introduction to the Calculation and Application of Hydrogeological Parameters
Cao Hui, Jiao Zhiliang, Fu Yabing
2015, 29(2): 73-75,99. doi: 10.3969/j.issn.1007-2993.2015.02.005
[Abstract](31) [PDF 753KB](12)
Abstract:
Combining with the data of field pumping tests and laboratory tests, this paper discusses the scope of application of different hydrogeological parameters in engineering investigation. Problems that should be paid attention to in the application of parameter calculation are also presented. The experimental data show that permeability coefficient with pumping tests is 10 to 14 times of the results of seepage tests. Influence radius is 5.8 to 17.7 times of the Dupuit influence radius. And this study analyzes the reasons for this situation, pointing out that different calculation methods of hydrogeological parameters should be selected according to different requirements in engineering practice. Finally, the problems on parameter calculation (hydraulic conductivity, discharge coefficient and specific yield) process and application process are analyzed. Has some significance for understanding the various hydrogeological parameters. The results have the benefit for understanding the various hydrogeological parameters.
The Statistical Relationship between Panzhihua Area Typical Soil Layer Shear Wave Velocity and Depth
Zhao Jing, Li Jianliang, Li Fuhai
2015, 29(2): 76-78,104. doi: 10.3969/j.issn.1007-2993.2015.02.006
[Abstract](37) [PDF 749KB](11)
Abstract:
The shear wave data of 338 testing points had been gotten from a lot of engineering geology drilling holes in Panzhihua area. Because of more testing points for Xigeda clay rock and Xigeda silty mudstone, shear wave datas of the two sorts of soil were analyzed statistically, using linear-formed (vs=a + bH), exponential-formed (vs=cHd) and polynomialformed (vs=e+fH+gH2) shear wave experience formula. Then the experience formulae of shear wave for the two types of soil were obtained, which could show the common rule that shear wave changed along with the depth. The shear wave datas will can be speculated in the engineering sites lack of the wave datas, in order to give reference in the classification of engineering site sort and calculate subsoil earthquake response, etc.
Back Analysis Research and Security Assessment of PCMW Engineering Method on Retaining Structure of Deep Foundation
Wang Jiuhong, Fan Qinjian
2015, 29(2): 79-83. doi: 10.3969/j.issn.1007-2993.2015.02.007
[Abstract](38) [PDF 1961KB](10)
Abstract:
PCMW engineering method is a new support form and has been applied in foundation pit engineering. On basis of situ inclinometer data measured from an excavation case in Nanjing, the deformation curve is fitted by the least squares method, and bending moment value of pipe pile is obtained through inversion calculation. Then security of the supporting form is assessed and its feasibility is verified for foundation pit engineering. The results show that the polynomial optimal times for the least squares fitting curve is 6 times and the bending moment obtained by back analysis can well reflect the actual moment of the retaining structure in middle depth of the foundation pit. The internal forces of supporting pile play a low degree, so safety margin is large. It is concluded that PCMW engineering method on retaining structure is safe.
Construction Technology of Separate Pit Applied to Control Long Side Effect of Foundation Pit
Song Dexin, Tao Zhu, Fan Qinjian
2015, 29(2): 84-89. doi: 10.3969/j.issn.1007-2993.2015.02.008
[Abstract](58) [PDF 3057KB](8)
Abstract:
Construction technology of separate pit divides a large foundation pit into several small foundation pits. Using the method of "time——space effect", successively construction often can effectively control the deformation of the long side of pit and ensure the safety of pipelines and buildings around. Based on a typical case of excavation, the paper analyzed influence of the surrounding environment in the case of zoned excavation and overall construction by Plaxis3D dimensional finite element numerical simulation. Then the simulated results were compared with the measured monitoring data. It is shown that construction technology of separate pit can effectively reduce the deformation of the long side of pit.
Foundation Treatment Technology
Study on Microscopic Characters of Soft Soil in the Pearl River Delta Vacuum Preloading and Electro-Kinetics Experiment
Zhang Bilong, Li Hongyi, Zhang Chengbo
2015, 29(2): 90-94. doi: 10.3969/j.issn.1007-2993.2015.02.009
[Abstract](33) [PDF 1300KB](7)
Abstract:
In this paper, vacuum preloading and electro-kinetics(electro-osmosis) role of the Pearl River Delta sea(River) of soft soil as the object of study. We conduct studies using scanning electron microscopy on the mierostrueture of the above two kinds of clay in the basic unit of the pore number and porosity, the basic unit of the average equivalent pore size and average pore size, the basic unit of the abundance and size distribution index, the basic unit of probability entropy and pore aspects. On this basis, compared the results of vacuum preloading and electro-kinetics(electro-osmosis) experiments. Experimental resuits show that, compared with the vacuum preloading and electro-osmosis test, clay after electro-kinetics trials, obvious damage of soil particles. The small pores gradually squeezed disappear or the pores of self adjustment and communicated with each other to form large pores. Soft soil by cellular space frame structure gradually into the skeleton structure agglomerate fiocculation structure, vacuum preloading and electro-kinetics of the more obvious reinforcement effect. Provide a reference for the construction of marine deposit area of Pearl River Delta region.
Application of Bearing Layer Reinforcement around Pile Tip by New Composite Curtain Grouting Technique
Lu Wenlong, Liu Lian
2015, 29(2): 95-99. doi: 10.3969/j.issn.1007-2993.2015.02.010
[Abstract](24) [PDF 2413KB](8)
Abstract:
This paper Proposed a new composite curtain grouting technique, which solved the bearing layer defection problem of pile in the gravel filling karst area, weathering granite region and gravel zone. This technique prevented high pressure jet flow of composite grouting cutting the soil around the pile directly. Thus the bearing capacity of pile foundation could he guaranteed. Basing on the principle, the construction technology, described parameters of the new composite curtain grouting and the correctness of this method was verified. The new curtain composite grouting technique provided a reference for similar projects.
Correction about Settlement Calculation Method of CFG Pile Composite Foundation
Zhang Qinxi, Zheng Yuping, Chen Peng
2015, 29(2): 100-104. doi: 10.3969/j.issn.1007-2993.2015.02.011
[Abstract](28) [PDF 799KB](9)
Abstract:
In the design of composite foundation, in addition to meeting the foundation bearing capacity also meeting the ground deformation design requirements. At present, the deformation calculation of composite foundation widely adopted semitheoretical, semi empirical method from ground handling practices, but a lot of settlement monitoring data show the real sedimentation of CFG pile composite foundation far less than calculated value which calculate according to standardized methods. This article aims at the defect of settlement calculation methods which about CFG pile composite foundation and reference researches in natural ground and composite foundation. This article proposes a correction formula and some personal opinions to get the goal which is safe and reliable economic and practical in the same time provide a theoretical basis for settlement calculation of CFG pile composite foundation.
Optimization Design Method of Cement Fly-ash Gravel Pile Composite Foundation Based on HPSO Algorithm
Liu Wenbin, Qi Zhendong
2015, 29(2): 105-108. doi: 10.3969/j.issn.1007-2993.2015.02.012
[Abstract](21) [PDF 721KB](8)
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 multi-parameters of cement fly-ash gravel (CFG) pile composite foundation, 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 quantity of CFG 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 parameters of CFG pile composite foundation are identified adaptively during computation. This method was used in the design of CFG pile composite foundation in a project, and the results show that HPSO algorithm is effective in designing of cement fly-ash gravel pile composite foundation, which can reduce engineering cost and increase economic efficiency effectively.

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