MEASUREMENT AND EVALUATION OF THE VERTICAL STRESS DISTRIBUTION AT SOIL-TIRE INTERFACE IN CULTIVATED SOIL UNDER STATIC CONDITIONS

2017 ◽  
Author(s):  
Chunxia Jiang ◽  
Zhixiong Lu ◽  
Shrinivasa K Upadhyaya
Keyword(s):  
Stress Distribution ◽  
Vertical Stress ◽  
Cultivated Soil ◽  
Measurement And Evaluation ◽  
Static Conditions

Measurement and Analysis of the Vertical Stress Distribution within a Cultivated Soil Volume under Static Conditions

2019 ◽  
Vol 62 (4) ◽  
pp. 1035-1043
Author(s):  
Chunxia Jiang ◽  
Zhixiong Lu ◽  
Shrinivasa K. Upadhyaya ◽  
Muhammad Sohail Memon
Keyword(s):  
Stress Distribution ◽  
Empirical Relationship ◽  
Pressure Sensors ◽  
Quadratic Function ◽  
Soil Surface ◽  
Vertical Stress ◽  
Inflation Pressure ◽  
Cultivated Soil ◽  
Soil Volume ◽  
Static Conditions

Abstract. One of the important considerations of soil-tire interaction research is the stress distribution in the topsoil and within the cultivated soil volume due to tires. This stress distribution influences trafficability, ride performance, and tractive performance. In this study, a two-wheel-drive tractor and a group of piezoelectric pressure sensors were used at different tire loads and inflation pressures to (1) measure the vertical stress under three tire loads with three inflation pressures and determine the influence of these two parameters on the vertical stress in the topsoil, as measured by sensors with their upper surfaces at an initial depth of 50 mm within the soil volume; (2) develop an empirical relationship between the vertical stress and the depth beneath the soil surface, the tire load, the inflation pressure, and the lateral sensor distance from the tire centerline using multiple linear regression; and (3) analyze the effects of tire load and inflation pressure on vertical stress to contribute to the understanding of soil compaction processes based on the equation we developed. All vertical stress measurements were conducted when traffic was applied to the soil by the left front tire of the tractor, with forward motion of the tractor stopped before the left rear tire reached the sensors. The results indicated that (1) when the inflation pressure decreased, the soil-tire interface stress curve became smooth and the peak value of stress gradually moved to a point near the edge of the tire, whereas when the inflation pressure was higher, the peak stress value occurred in the center of the tire; (2) low inflation pressure significantly reduced the maximum vertical stress; (3) the vertical stress was influenced by all four factors investigated in this study; and (4) the stress within the soil volume varied as a quadratic function of the inflation pressure at a given tire load, and it varied as a linear function of tire load at a given inflation pressure. Keywords: Stress distribution, Tire load, Tire inflation pressure.

scholarly journals Stress and deformation analysis of gob-side pre-backfill driving procedure of longwall mining: a case study

2021 ◽  
Author(s):  
Rui Wu ◽  
Penghui Zhang ◽  
Pinnaduwa H. S. W. Kulatilake ◽  
Hao Luo ◽  
Qingyuan He
Keyword(s):  
Rock Mass ◽  
Stress Distribution ◽  
Coal Seam ◽  
Abutment Pressure ◽  
Longwall Mining ◽  
Vertical Stress ◽  
Floor Level ◽  
Working Face ◽  
Floor Heave ◽  
Stress And Deformation

AbstractAt present, non-pillar entry protection in longwall mining is mainly achieved through either the gob-side entry retaining (GER) procedure or the gob-side entry driving (GED) procedure. The GER procedure leads to difficulties in maintaining the roadway in mining both the previous and current panels. A narrow coal pillar about 5–7 m must be left in the GED procedure; therefore, it causes permanent loss of some coal. The gob-side pre-backfill driving (GPD) procedure effectively removes the wasting of coal resources that exists in the GED procedure and finds an alternative way to handle the roadway maintenance problem that exists in the GER procedure. The FLAC3D software was used to numerically investigate the stress and deformation distributions and failure of the rock mass surrounding the previous and current panel roadways during each stage of the GPD procedure which requires "twice excavation and mining". The results show that the stress distribution is slightly asymmetric around the previous panel roadway after the “primary excavation”. The stronger and stiffer backfill compared to the coal turned out to be the main bearing body of the previous panel roadway during the "primary mining". The highest vertical stresses of 32.6 and 23.1 MPa, compared to the in-situ stress of 10.5 MPa, appeared in the backfill wall and coal seam, respectively. After the "primary mining", the peak vertical stress under the coal seam at the floor level was slightly higher (18.1 MPa) than that under the backfill (17.8 MPa). After the "secondary excavation", the peak vertical stress under the coal seam at the floor level was slightly lower (18.7 MPa) than that under the backfill (19.8 MPa); the maximum floor heave and maximum roof sag of the current panel roadway were 252.9 and 322.1 mm, respectively. During the "secondary mining", the stress distribution in the rock mass surrounding the current panel roadway was mainly affected by the superposition of the front abutment pressure from the current panel and the side abutment pressure from the previous panel. The floor heave of the current panel roadway reached a maximum of 321.8 mm at 5 m ahead of the working face; the roof sag increased to 828.4 mm at the working face. The peak abutment pressure appeared alternately in the backfill and the coal seam during the whole procedure of "twice excavation and mining" of the GPD procedure. The backfill provided strong bearing capacity during all stages of the GPD procedure and exhibited reliable support for the roadway. The results provide scientific insight for engineering practice of the GPD procedure.

Vertical Stress Distributions of a Thin Rectangular Steel Wall Under Compression and in-Plane Bending

2020 ◽  
Vol 20 (08) ◽  
pp. 2050090
Author(s):  
Yang Lv ◽  
Jia-Qi Lv ◽  
Zheng Zhao
Keyword(s):  
Shear Strength ◽  
Stress Distribution ◽  
Shear Wall ◽  
Vertical Stress ◽  
Thin Wall ◽  
Effective Width ◽  
Steel Shear Wall ◽  
Gravity Load ◽  
Plane Bending ◽  
Minimum Stress

A thin rectangular steel wall in a steel shear wall structure always simultaneously sustains the lateral load and the gravity load. The gravity load can affect the shear strength of a steel shear wall. However, this effect is not considered in most of the research and standards, which may lead to potential danger in practice. From the previous study of the authors, the shear strength reduction was not only influenced by the load magnitude but also by the vertical stress distribution. For a simply-supported thick square wall, i.e. width to thickness ratio smaller than 100, the stress distribution can be accurately described in a cosine form. However, for a thin wall under compression and in-plane bending, the cosine distribution will largely overestimate the vertical stress, especially when the walls enter the post-buckling condition. To narrow the knowledge gap, this paper proposed a vertical stress distribution in a three-segment form, i.e. in both edge-segments, a combination of linear and cosine functions from the edge stresses to the minimum stress, while in the middle segment, the stress distribution is constant and equal to the minimum stress. Two strategies, i.e. effective width method and Bedair’s method, are chosen to determine the width of the edge portion. A finite element model (FEM) is developed to evaluate the proposed distribution. The FEM has been verified using the results of our own experiments and tests done by Zaraś et al. The results show that the proposed three-segment stress distribution can well describe the behavior of thin walls of different slendernesses and stress gradients. The cosine distribution obtained from theoretical solution and the effective width model by Bedair are also discussed.

Calculation of the Vertical Stress Distribution Beneath Groups of Footings

Géotechnique ◽  
1965 ◽  
Vol 15 (4) ◽  
pp. 396-408
Author(s):  
Robert L. Kondner ◽  
Raymond J. krizek
Keyword(s):  
Stress Distribution ◽  
Vertical Stress

Predicted tyre–soil interface area and vertical stress distribution based on loading characteristics

2015 ◽  
Vol 152 ◽  
pp. 52-66 ◽  
Author(s):  
Per Schjønning ◽  
Matthias Stettler ◽  
Thomas Keller ◽  
Poul Lassen ◽  
Mathieu Lamandé
Keyword(s):  
Stress Distribution ◽  
Vertical Stress ◽  
Interface Area ◽  
Soil Interface

Vertical stress distribution under tractor wheeling in a partially deep loosened typic paleustalf

1989 ◽  
Vol 13 (1) ◽  
pp. 1-12 ◽  
Author(s):  
J. Blackwell ◽  
R. Horn ◽  
N.S. Jayawardane ◽  
R. White ◽  
P.S. Blackwell
Keyword(s):  
Stress Distribution ◽  
Vertical Stress
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