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Stabilitation Research of the Tunnel Anchorage of Dadu River Bridge in Luding in Yaan to Kangding Expressway
Wen Lina,
Cheng Qiangong,
Cheng Qiang,
Guo Xifeng
Issue:
Volume 5, Issue 4, July 2017
Pages:
196-204
Received:
12 June 2017
Published:
14 June 2017
Abstract: Based on features of indoor rock mechanics test, the in situ test and rock mass classification result, through established numerical analysis model of the tunnel anchor model drawing test, using the model observed values of surrounding rock deformation, using intelligent inversion method to inverting the displacement creep and mechanical parameters and provides more accurate and reasonable rock mass mechanics parameters to analyze the stability of surrounding rock tunnel anchorage of Dadu River bridge from Yaan to Kangding expressway in Lu Ding. This paper uses LSSVM and PSO analysis model and FLAC3D numerical methods to realize the intelligent displacement inversion. Through the anchor parameters inversion of the model, and establish the solid bridge anchor numerical model, analysis of anchor tunnel excavation, load and overload condition of deformation and internal force, and then analyze the stability of tunnel anchor. Under the design load, anchorage roof and side wall stress relaxation zone in the plastic zone, floor rock mass basic in flexible working condition. Increase the force of main cable and 7P, shear failure and anchor rock contact area, increase the displacement of anchorage is nonlinear. Under the overload condition, the anchor rock rupture increased significantly and produce compression, the plastic zone to the development of deep surrounding rock anchorage above, failure mode for compressive shear failure. The conclusion to provide technical support for tunnel anchor design, at the same time, provide reference for similar projects.
Abstract: Based on features of indoor rock mechanics test, the in situ test and rock mass classification result, through established numerical analysis model of the tunnel anchor model drawing test, using the model observed values of surrounding rock deformation, using intelligent inversion method to inverting the displacement creep and mechanical parameters...
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Structural Evaluation of the Effect of Pulverized Palm Kernel Shell (PPKS) on Cement-Modified Lateritic Soil Sample
Olutaiwo Adewale,
Ajisafe Segun,
Adanikin Ariyo
Issue:
Volume 5, Issue 4, July 2017
Pages:
205-211
Received:
20 April 2017
Accepted:
2 May 2017
Published:
19 June 2017
Abstract: There have been global efforts to reduce environmental pollution of agricultural and industrial waste products by utilizing such wastes as stabilizing agents to improve soils for various uses, especially road construction. In this research, lateritic soil sample obtained from a borrow pit was tested with varying percentages of Pulverized Palm Kernel Shell (PPKS). The soil was classified as A-6 (AASHTO classification) using standard soil laboratory tests. Laboratory tests such as Atterberg Limits, Compaction, Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) were conducted on the soil + PPKS mix only and also on soil + PPKS + 3% Ordinary Portland Cement (OPC) mix. The liquid limit (LL) and plasticity index (PI) values decreased steadily with increase in PPKS while the plastic limit (PL) value increased with up to 4% PPKS addition after which the values started decreasing. The shrinkage limit (SL) value increased with a peak value at 8% PPKS addition after which the values began to decrease. The Optimum Moisture Content (OMC) results on PPKS addition increased from 16% to 19.5% while the Maximum Dry Density (MDD) decreased by 45.18% from 1.669g/m3 to 0.915g/m3. Addition of PPKS decreased the Unsoaked CBR by 10.79% from 68.60 to 61.20% while the Soaked CBR increased by 74.12% from 18.05% to 69.75%. UCS values for the lateritic soil and PPKS for the uncured sample, at 7 days and 14 days had peak values of 85.03, 96.46 and 100.44 respectively. From the study, it can be concluded that the properties of the Lateritic soil improved when stabilized with Cement and pulverized palm kernel shell compared to when it was stabilized with pulverized palm kernel shell alone.
Abstract: There have been global efforts to reduce environmental pollution of agricultural and industrial waste products by utilizing such wastes as stabilizing agents to improve soils for various uses, especially road construction. In this research, lateritic soil sample obtained from a borrow pit was tested with varying percentages of Pulverized Palm Kerne...
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Comparative Study of Labor-Based Method and Machine-Based Method at Rural Road Construction and Maintenance in Jimma Zone, Oromia Region, Ethiopia
Anwar Kassahun Dunffa,
Emer Tucay Quezon,
Elmer De Castro Agon
Issue:
Volume 5, Issue 4, July 2017
Pages:
212-219
Received:
11 April 2017
Accepted:
20 April 2017
Published:
21 June 2017
Abstract: The construction of physical infrastructure is contributory for poverty alleviation in every country. The road is one of the major components which is very significant in Ethiopia due to lack of highly developed infrastructure, particularly in the rural road sector. Selection of the appropriate road construction and maintenance methods such as labor-based method or machine-based method is necessary to be financially viable. Most rural road construction projects usually suffer from the problem of selecting the appropriate technology for the proposed project and implementation of the chosen technology. In Ethiopia, Universal Rural Road Access Program (URRAP) is an employment-intensive program for employment purpose as a first step, out of poverty using labor-based road construction. However, there are problems, constraints, and challenges encountered when implementing labor-based method leading to enforce the mobilization of machines. The aim of this research study is to carry out the comparative analysis of ongoing and finished rural road projects in Jimma Zone and to establish a qualitative and quantitative merit of various technologies used in rural road construction and maintenance. Results showed from financial cost comparison, the labor - based method was 47% cheaper than a machine-based method to carry out the same tasks. On the other hand, the share of unskilled average direct labor cost comprised of an astounding 65% more of the total direct cost of a labor-based method. Also, labor-based method directly employed 300 unskilled laborers per workday for a month to complete 1.0 km section of a rural road.
Abstract: The construction of physical infrastructure is contributory for poverty alleviation in every country. The road is one of the major components which is very significant in Ethiopia due to lack of highly developed infrastructure, particularly in the rural road sector. Selection of the appropriate road construction and maintenance methods such as labo...
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Calculation and Analysis of Interaction Between Buried Pipeline and Soil
Issue:
Volume 5, Issue 4, July 2017
Pages:
220-224
Received:
19 July 2017
Published:
19 July 2017
Abstract: In order to gain a clear idea of mechanism of stress and deformation for buried pipeline, the soil pressure on the buried pipeline computation boiled down to solving the gravity field in two-dimensional elastic medium embedded with an elastic ring hole stress concentration problem. Based on considering the deformation coordination of pipe-soil contact surface, the stress function method was used to derive the elasticity solution of the soil pressure around the pipeline. It established the analytical relationship between pressure around the pipeline and pipeline section stiffness, providing a new way for pipeline force calculating. Example analysis indicated that the pipe circumferential stress using the stress function method was quite closed to the finite element calculation and the simplified stress distribution around pipeline was convex parabola. Through the calculation of pipe-soil interaction, it was further indicated that besides the positive soil stress acting on the buried pipeline, there had large value of shear stress along the pipeline. The role of this part should be considered in calculating the force acting on the buried pipeline.
Abstract: In order to gain a clear idea of mechanism of stress and deformation for buried pipeline, the soil pressure on the buried pipeline computation boiled down to solving the gravity field in two-dimensional elastic medium embedded with an elastic ring hole stress concentration problem. Based on considering the deformation coordination of pipe-soil cont...
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Strain-Based Finite Element Analysis of Stiffened Cylindrical Shell Roof
Issue:
Volume 5, Issue 4, July 2017
Pages:
225-230
Received:
11 June 2017
Accepted:
28 June 2017
Published:
24 July 2017
Abstract: A new triangular cylindrical shell finite element is used to obtain an elastic linear analysis of a cylindrical shell roof. The element’s displacement fields are in terms of curvilinear coordinates, satisfy the exact requirement of rigid body modes of deformation and have five degrees of freedom at each of the three corner nodes. The efficiency of the developed element is first tested and then applied to analyze stiffened cylindrical shell roof. The results of the displacement and stress resultant along the stiffener are presented and a parametric study is carried out to find the effect of the varying geometry of the stiffener and the effect of axis rotation of the beam on the level of the internal forces.
Abstract: A new triangular cylindrical shell finite element is used to obtain an elastic linear analysis of a cylindrical shell roof. The element’s displacement fields are in terms of curvilinear coordinates, satisfy the exact requirement of rigid body modes of deformation and have five degrees of freedom at each of the three corner nodes. The efficiency of ...
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Probabilistic Analysis of Joint Work Between Pile and Soil
Hongying Jiang,
Jiaming Lu
Issue:
Volume 5, Issue 4, July 2017
Pages:
231-234
Received:
1 August 2017
Published:
2 August 2017
Abstract: Based on the two-dimensional simulation experiment and used the stochastic theory, the regulation of load sharing ratio between pile and soil in composite foundation during construction and consolidation settlement of soil is studied. A simplified probabilistic model is proposed to estimate the load sharing ratio. It provides a reference basis for better study of the predictability of composite foundation and other structural prediction studies based on a variety of materials.
Abstract: Based on the two-dimensional simulation experiment and used the stochastic theory, the regulation of load sharing ratio between pile and soil in composite foundation during construction and consolidation settlement of soil is studied. A simplified probabilistic model is proposed to estimate the load sharing ratio. It provides a reference basis for ...
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Research on the Vertical Setback Problem of Steel Bundled Tube Structure
Hao Yong,
Li Yansong,
Jiu Zhenggang,
Zhang Tao,
Wang Futian,
Zhang Xusheng
Issue:
Volume 5, Issue 4, July 2017
Pages:
235-241
Received:
13 August 2017
Published:
14 August 2017
Abstract: To study the mechanical performance of steel bundled-tube structures and find the reasonable setback scheme, the 18 calculation model with different setback based on the same bottom, height as well as the volume were designed. The effect of different setback methods on performance indexes such as natural vibration period of the structure, stiffness was analyzed. Stress total enhancement ratio and reference enhancement ratio are introduced to study the distribution rule of the spandrel beam stress under different vertical setback methods. The distribution rule of column stress was also analyzed. The results show that the changing rule of the equivalent wind effect coefficient is the same as the basal shearing force and basal anti-overturning moment. Reference enhancement ratio of the spandrel beam is a fixed value at a certain height and volume. Total stress enhancement ratio of the spandrel beam is mainly related to the remained height. Vertical setback causes abrupt stress in the columns. The setback influence on the columns is less than that on the beams, and the abrupt stress stories are also less. It is advised that the location of the initial setback should be as far as possible from the embedded end. The reasonable setback method should be uniform and symmetric.
Abstract: To study the mechanical performance of steel bundled-tube structures and find the reasonable setback scheme, the 18 calculation model with different setback based on the same bottom, height as well as the volume were designed. The effect of different setback methods on performance indexes such as natural vibration period of the structure, stiffness...
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Study on the Attenuation Mechanism of Unsaturated Residual Soil Under Rainfall Condition -A Case Study of the Tiller and Sediment Soil in Qishan Landslide, China
Liu Junzhe,
Zuo Changqun,
Song Yingjie,
Ren Rui,
Li Zi
Issue:
Volume 5, Issue 4, July 2017
Pages:
242-253
Received:
13 August 2017
Published:
14 August 2017
Abstract: In the most area of the Southern part in China, the high-intensity and large-scale rainfalls would easily cause some natural disasters like landslide and mud slide in the area of which the geological conditions are not stable and could lead to mass casualty and a great loss in economy. The paper targets the tuff residual soil in Qishan, Yongtai city, Fujian Province of China as the investigated subject, getting the mineral composition of the soil mass through X-ray experiment, analyzing the micro structure and mineral compositions in soil mass in qualitative, getting the parameters of shear strength of the soil mass by taking quadruple shear test to the soil samples which were in different level of water content and wet-dry cycle times, making analysis to the micro structure of test samples by using electrical scanning, and using the Matlab software to make calculation about the micro-structural parameters to analyze it in quantitative and forming the fitting relations among water content, wet-dry cycle times, vertical load and micro-structural parameters of soil mass so that the intensity attenuation mechanism of the unsaturated residual soil under the condition of rainfall would be revealed.
Abstract: In the most area of the Southern part in China, the high-intensity and large-scale rainfalls would easily cause some natural disasters like landslide and mud slide in the area of which the geological conditions are not stable and could lead to mass casualty and a great loss in economy. The paper targets the tuff residual soil in Qishan, Yongtai cit...
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