The Influence of Pavement Construction on Embankment Settlement in Highway Extension Project

2013 ◽  
Vol 361-363 ◽  
pp. 1787-1793
Author(s):  
Xian Lin Wei ◽  
Yi Min Wang ◽  
Ze Min Zeng ◽  
Luo Zhang
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Composite Foundation ◽  
Standard Requirement ◽  
Construction Period ◽  
Small Influence ◽  
Load Carrying ◽  
Pavement Construction ◽  
Layer Deformation

In order to reduce the soft soil layer deformation due to pavement construction, equal preloading of pavement is usually adopted after embankment filling in soft ground region. But as the ground treatment effect of pile-supported and geosynthetic reinforced embankment is satisfactory with great load-carrying ability, the necessity of applying equal preload is worth discussing. Combined with the practice of Guangzhou-Sanshui expressway widening project, the settlements in surveying sections during the paving construction period in extension area were monitored. The monitoring data shows that pavement load had small influence on embankment settlement: the uneven settlement between newly widen and existing road is small and the post-construction settlements are controlled within the standard requirement. On the premise of guaranteeing the construction quality of composite-foundation and filling compaction degree, it is unnecessary to take equal preloading to avoid excessive embankment settlement caused by the pavement structure.

scholarly journals Study of Construction Techniques of Highways and Bridges on Soft Soil Foundation

2015 ◽  
Vol 2 ◽  
pp. 39
Author(s):  
Hainan Zheng
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Foundation Construction ◽  
Safety Issues ◽  
Construction Techniques ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
The Cost

<p>The quality of highways and bridges’ foundation construction influences the overall quality of the projects directly. The soft soil layer shall be investigated in advance during construction in order to analyse and identify the specific reinforcement and processing approaches. The cost, processed effects and safety issues shall be considered prior to reinforcement. Different reinforcement approaches can be used in order to save the cost and ensure the quality of soft soil foundation reinforcement. This paper discusses the preparation of soft soil foundation construction and the technology involved in the construction of highways and bridges on soft soil foundation. It is expected that the study could provide some references to professionals.  </p>

scholarly journals Analysis of Causes of CFG Pile Necking in Saturated Soft Soil Layer and Its Control Measures

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Wang Hang
Keyword(s):  
Fly Ash ◽  
Soft Soil ◽  
Soil Layer ◽  
Reference Value ◽  
Composite Foundation ◽  
Control Measures ◽  
Effective Control ◽  
Foundation Treatment ◽  
Soft Foundation ◽  
Cfg Pile

In recent years, composite foundation technology has been widely used in foundation treatment. Composite foundation theory has become an important research topic in the field of geotechnical engineering. CFG pile (Abbreviation of cement, fly ash, and gravel pile) in composite foundation is one of the commonly used technologies. It has advantages such as simple construction, reliable quality and low cost. When it is used in soft foundation treatment, it significantly improves the bearing capacity, reduces settlement, and turns waste (fly ash) to treasure, which benefits economic and social significantly. During construction, various defects in construction quality will affect the effect of soft foundation treatment. CFG pile necking is one of the more representative quality defects. This paper combined some project examples to analyze the causes of CFG pile necking and develop effective control measures for it which has a certain reference value towards the quality control of the technology

scholarly journals Influence of Slope Direction on the Soil Seed Bank and Seedling Regeneration of Castanopsis hystrix Seed Rain

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 500
Author(s):  
Zong Zhao ◽  
Yong Liu ◽  
Hongyan Jia ◽  
Wensheng Sun ◽  
Angang Ming ◽  
...  
Keyword(s):  
Seed Bank ◽  
Temporal Dynamics ◽  
Soil Seed Bank ◽  
Soil Layer ◽  
Seed Rain ◽  
Seed Vigor ◽  
Study Results ◽  
The Impact ◽  
Mature Seeds

Objective: To investigate the impact of different slope directions on the quantity and quality of the soil seed bank and seedling germination process of Castanopsis hystrix plantations. Method: Fixed sample plots in forest stands of Castanopsis hystrix were established on different slope directions (sunny slope, semi-sunny slope, semi-shady slope, and shady slope). The characteristics of the forest stand were investigated, and per-wood scaling was carried out. The temporal dynamics of the seed rain and seed bank were quantified using seed rain collectors and by collecting soil samples from different depths. The quantity and quality of the seeds were determined, and the vigor of mature seeds was measured throughout the study. Results: (1) The diffusion of Castanopsis hystrix seed rain started in mid-September, reached its peak from late October to early November, and ended in mid-December. (2) The dissemination process, occurrence time, and composition of the seed rain varied between the different slope directions. The seed rain intensity on the semi-sunny slope was the highest (572.75 ± 9.50 grains∙m−2), followed by the sunny slope (515.60 ± 10.28 grains∙m−2), the semi-shady slope (382.13 ± 12.11 grains∙m−2), and finally the shady slope (208.00 ± 11.35 grains∙m−2). The seed rain on the sunny slope diffused earliest and lasted the longest, while the seed rain on the shady slope diffused latest and lasted the shortest time. Seed vigor and the proportion of mature seeds within the seed rain were greatest on the semi-sunny slope, followed by the sunny slope, semi-shady slope, and the shady slope. (3) From the end of the seed rain to August of the following year, the amount of total reserves of the soil seed banks was highest on the semi-sunny slope, followed by the sunny slope then the semi-shady slope, and it was the lowest on the shady slope. The amount of mature, immature, gnawed seeds and seed vigor of the soil seed bank in various slope directions showed a decreasing trend with time. The seeds of the seed bank in all slope directions were mainly distributed in the litter layer, followed by the 0–2 cm humus layer, and only a few seeds were present in the 2–5 cm soil layer. (4) The seedling density of Castanopsis hystrix differed significantly on the different slope directions. The semi-sunny slope had the most seedlings, followed by the sunny slope, semi-shady slope, and the shady slope. Conclusions: The environmental conditions of the semi-sunny slope were found to be most suitable for the seed germination and seedling growth of Castanopsis hystrix, and more conducive to the regeneration and restoration of its population.

Application Research on Composite Foundation of Rammed Soil-Cement Piles Applied in the Da-Guang Expressway from Gu'an to Shenzhou

2013 ◽  
Vol 740 ◽  
pp. 655-658
Author(s):  
Huan Sheng Mu ◽  
Ling Gao
Keyword(s):  
Soft Soil ◽  
Composite Foundation ◽  
Application Research ◽  
Action Mechanism ◽  
Foundation Design ◽  
Soil Cement ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Cement Soil ◽  
Capacity Characteristic

Through the practice of tamped cement soil pile in treatment of soft soil foundation in Guan to Shenzhou section of Daqing-Guangzhou Expressway, the author expounds the action mechanism of rammed soil cement pile, composite foundation design points and calculation method of bearing capacity characteristic value.

scholarly journals CONCERNING THE EXTRACTION OF A SLACK SOIL LAYER FROM COMPRESSIBLE THICKNESS OF FOUNDATION STRATUM OF FINITE WIDTH FOUNDATIONS

2019 ◽  
Vol 7 (4) ◽  
pp. 49-56
Author(s):  
Zaven Ter-Martirosyan ◽  
Armen Ter-martirosyan ◽  
Valery DEMYANENKO
Keyword(s):  
Analytical Solutions ◽  
Soft Soil ◽  
Soil Layer ◽  
Horizontal Displacement ◽  
Creep Model ◽  
Shear Stresses ◽  
Finite Width ◽  
Relative Depth ◽  
Weak Layer ◽  
Horizontal Displacements

The paper provides a quantitative assessment of the deflected mode of foundation stratum of finite width foundation, in the compressible thickness of which there is a slack clay soil layer. A number of criteria for assessing the possibility or impossibility of extruding a slack layer depending on its strength and rheological properties, as well as the relative thickness of the layer to its length (h/l) and the relative depth of the layer (h/d) have been given. Closed analytical solutions are given to determine the rate of Foundation precipitation depending on the rate of extrusion of the weak layer, including taking into account the damped and undamped creep. The analytical solutions in the article are supported by the graphical part made with the help of the Mathcad program. Plots of changes in shear stresses in the layer along the x axis at different distances from the axis and at different values 0, contours of horizontal displacement velocities in the weak layer at different distances from the x axis, plots of horizontal displacement velocities in the middle of the weak layer and plots of horizontal displacement velocities in the weak layer at different distances from the x axis are given. As a calculation model for describing the creep of a slack layer, rheological ones of the soil using power and hyperbolic functions and their modifications have been considered. In addition, most modern rheological models that take into account soil hardening during creep have been considered. Based on these models, the problem is solved by means analytical and numerical methods using the Mathcad PC and the PLAXIS PC according to the Soft Soil Creep model. The graphical part shows the isofields of horizontal displacements for 300 days and 600 days and the corresponding contours of horizontal displacements.

scholarly journals Optimization of the design and technological parameters of an active ripper of a combined working body

2021 ◽  
Vol 37 ◽  
pp. 00068
Author(s):  
S. A. Ivanaisky ◽  
M. A. Kanaev ◽  
Y. A. Kirov ◽  
M. S. Ivanaisky ◽  
S. V. Denisov
Keyword(s):  
Soil Layer ◽  
Winter Period ◽  
Technological Parameters ◽  
High Quality ◽  
Quality Performance ◽  
Soil Cultivation ◽  
Surface Moisture ◽  
Tillage Operation ◽  
Working Bodies

The research objective is to improve the quality of soil loosening using combined working bodies for surface moisture-retaining soil cultivation. The efficiency of accumulation and conservation of precipitation in the autumn-winter period depends on the method of post-harvest soil cultivation. One of them is the autumn surface water-retaining treatment, which makes it possible to increase the efficiency of the processes of accumulation and conservation of moisture due to the deeper loosening of the cultivated soil layer. During loosening and mulching, the top layer of the soil contributes to the accumulation and preservation of moisture not only in the upper but also in deeper soil horizons. However, the used tillage tools do not fully solve the problem of the high-quality performance of surface moisture-retaining soil cultivation. The article presents the results of studies of the degree of influence of geometric and technological parameters of the additional active cultivator on the quality of surface tillage. Based on the results of the research carried out, the technological process of performing the surface tillage operation has been improved and combined working bodies have been developed for its implementation.

Field Study of Improvement Mechanism of Geogrid-Reinforced and Pile-Supported Embankment

2014 ◽  
Vol 587-589 ◽  
pp. 928-933 ◽  
Author(s):  
Feng Lian ◽  
Zhi Liu ◽  
Jie Xu ◽  
Qiang Wang ◽  
Xian Hu Hu ◽  
...  
Keyword(s):  
Load Transfer ◽  
Soft Soil ◽  
Composite Foundation ◽  
Replacement Ratio ◽  
Floating Pile ◽  
Pile Cap ◽  
Soil Arch ◽  
Better Than ◽  
End Bearing Pile ◽  
Pile Supported Embankment

Two experimental areas in a highway soft soil ground treatment project in Guangdong Province were designed to investigate the improvement mechanism of geogrid-reinforced and pile-supported embankment(GRPS).The experimental results showed: In End-bearing Pile Area,the differential settlement between pile and soil was bigger than that of Floating Pile Area,so the bearing capacity of soil was exerted to a certain extent in Floating Pile Area. The bearing efficacy of soil below the pile cap was little, so the replacement ratio of composite foundation could be calculated according to the pile cap dimension. The load transfer efficacy of the geogrid was better than that of the soil arch. Five kinds of methods were used to evaluate the soil arch in the fill and it was indicated that the results calculated by the BS8006 method and Carlsson method was close to the experimental data which was smaller than results calculated by Hewlett method and Terzaghi method, bigger than Guido method. Through the analysis of the pile-soil stress ratio, the improvement mechanism of the two types of GRPS were revealed.

Model Test of Bearing Capacity of WasteTire Assembly Foundation on Soft Soil Layer

2021 ◽  
Vol 69 (7) ◽  
pp. 263-269
Author(s):  
Me ti ◽  
Tri Harianto ◽  
Abdul Rachman Djamaluddin ◽  
Achmad Bakri Muhiddin
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
Soft Soil ◽  
Soil Layer

KINEMATICS FEATURES OF HAMMER PERFORATED TILLAGE ROLL

2020 ◽  
pp. 13-19
Author(s):  
I. А. Sharonov ◽  
◽  
Yu. М. Isaev ◽  
V. I. Kurdyumov ◽  
◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Soil Layer ◽  
Point Of View ◽  
Lagrange Equations ◽  
Middle Volga Region ◽  
Perforated Cylinder ◽  
Winter Crops ◽  
Combined Impact ◽  
The Impact

The task of improving the quality of agricultural tools by improving the technological processes of their functioning, taking into account the kinematic features of the combined impact of working elements of tools on the soil environment is important from a scientific and technical point of view. To form the required structure and density of the soil layer at the depth of sowing, a hammer perforated tillage roller (HPTR) has been developed. The study aim is to improve the quality of post-sowing compaction and structuring of the soil layer in the seed location zone based on the development of an innovative design of HPTR that combines different effects on the treated environment. The object of research is the kinematic mode of operation of the HPTR, equipped with cylindrical hammers installed at the ends of the rod, which, in turn, are radially and pivotally installed on the axis of the gunFeature of offered HPTR is the excitation of hammer vibrations, which changes the kinematic parameters of the tillage tool as a whole. Lagrange equations of the second kind are used to describe the process of HPTR operation, which is represented as a system of material objects with several degrees of freedom. The conducted studies revealed the periodic nature of changes in the strength of the impact of HPTR on the soil. The obtained equations allow us to determine the features of the HPTR movement at different masses of a hollow perforated cylinder and cylindrical hammers. This is of great importance for increasing the efficiency of soil bolster destruction and creating the soil structure recommended for winter crops sown in the Middle Volga region.

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