Interface Friction between Organic Soil and Construction Materials

Understanding the basic phenomena controlling the mobilization of friction at the soil-solid surface contact is essential for such traditional foundation structures such as piles, micropiles and anchors. In this study, the interface frictional characteristics of organic soil and a variety solid construction materials, including concrete, steel, and wood, were investigated. The interface friction angles of organic soil-solid surfaces were determined for different water content and granular soil content. In addition, the relationship between surface roughnesses and interface friction was investigated. All tests in this study were performed using a direct shear test device under different normal stresses. The test results showed that the frictional resistance between construction material and organic soil is affected by the water and granular soil content of the organic soil, the type of material, and the surface roughness.

Key Engineering Materials, 2020

This study was carried out to undrestand some specific problems that limit safe design and construction of structures on problematic soils. An experimental study was undertaken to examine the influence of the rate of loading and moisture content on shear strength of organic soil. Influece of moisture content on interface friction between organic soil and structural material was also attempted. A commonly used soil in Iraq was prepared at varying moisture contents of 39, 57 and 75 %. The experimental results showed that the increase in water content will decrease the shear stress and the internal friction angle. An increase of the shear rate was found to decrease the shear stress and internal friction angle at all percetanges of water contents. Further, direct shear tests were carried out to detect the interface shear stress behavior between the organic soil and structural material. The results revealed that the increase in water content was shown to have significant negetavie effects on the interface internal friction and angle shear strength. Introductıon Shear strength is a significant property alongside other geotechnical properties in design and construction of structures. Shear strength often plays an essential role when any civil engineering application comes across soils which contain organic matter. Shear resistance is a concern factor at the construction of a standing construction equipment as well as at the end of construction in supporting the structure. Generally, organic soils posess low shear strength, and can be catigorized as 'problematic soils'. Accuracy in calculating the shear strength of these types of soils is limited to some variables, namely; origin of soil, moisture content, organic content, shear rate and degree of humification [1]. In the case of organic soil, the interface friction between the soil and construction material, such as wood, concrete and steel is found to be another important factor. One can argue that the shear strength of organic soils and hence, the angle of internal friction (peak or residual) is governed by several factors including; soil composition, initial stress state of the sample, soil structure, specimen size and rate of loading. The rate of loading, i.e. rate of strain, has been found to be one of the prominent factors influencing the obtained shear strength parameter [2]. Impact of the shear rate on the residual strength of cohesive soils was studied by many researchers [3, 4, 5]. In these studies, three types of residual strengths were observed when a slow shear rate was applied under drained condition followed by a fast shear rate. These residual strengths named by the effect of positive rate, neutral rate and negative rate. In addition, considerable works have been carried out on the performance of cohesionless soils under different shear rates [5, 6, 7]. Cassagrande and Shannon [6] were among the first to obtain the effect of strain rate on the shear resistance of soil. The researchers carried out triaxial tests on sands at confining pressures ranged from 30 to 90 kPa with strain rates up to 115 % per second. Cassagrande and Shannon [6] found that shear resistance of the dry sand has increased by approximately 10 % from static levels when tested at high rates of loading. The generated pore water pressure was dependent on the strain rate in the undrained triaxial tests. Therefore, the pore water pressure in the residual state was more likely dependent on the shear rate. In other words, the dependence of effective Key Engineering Materials

Bearing capacity and load-deformation response of geotechnical structures such as retaining walls, buried culverts, piles, etc., depend on the stress-displacement behavior of interfaces in the contact area with soil. So it is essential to determine the interface strength between soil and geotechnical structures to make a good estimation of load transfer between structures and soils. To provide some insight into the interface behavior between concrete and gravel soils, an experimental study was performed to evaluate the importance of various parameters. The parameters varied in this investigation were surface roughness (which include smooth to rough), soil gradation (well and poorly graded) and normal stress (0.05 N/mm2 to 0.20 N/mm2). Experimental results show that soil gradation and surface roughness of concrete specimens were significantly changes the interface friction angle. Shear strength at the interface increases with increase in normal stress and surface roughness. This study will be beneficial to the researchers and practicing engineers working in soil-structure interaction problems.

Shear strength is the principle engineering property which controls stability of soil mass under load. Its governs the bearing capacity of soil, stability of slopes in soils, the earth pressure against retaining structure and subgrade in highway. In soil structure interaction problems often becomes important to make a good estimation of friction of frictional resistance between ground and foundation. The information interface friction angle of soil against frictional surfaces is of great interest among research in soil structure interaction. Retaining wall is one of the important structure which are used mainly to retain soil mass hence need proper design. Present study includes series of DST to investigate the interface friction angle of different friction surfaces (jute, geotextile) with three soil samples (sand, murrum, clay). Using these friction values active earth pressure is evaluated by Rankine's, coulomb's method, and poncelet's , culmann's method.

Acta Technologica Agriculturae, 2018

Soil friction and soil adhesion increase the implement draft force and energy consumption particularly in the tools that have larger contact area with soil. The main ways of lowering the total draft force of the tillage tools include the use of proper materials in tools structures as well as application of the tools in appropriate soil moisture content condition. This paper investigates the effects of soil moisture content, contact surface material and soil texture on soil friction and soil adhesion coefficients. To measure the coefficients of soil friction and soil adhesion, a measurement system was developed at the University of Mohaghegh Ardabili. Experiments for each soil texture were performed at five levels of soil moisture content and four contact materials of steel, cast iron, rubber, and teflon with three replications. Results have shown that in all soil types, the effects of soil moisture content and contact materials had a significant effect on the coefficient of both soi...

There is the need to develop appropriate and efficient soil engaging tools and implements to optimize energy required to cultivate the land and enhance agricultural productivity and sustainability in Nigeria. Necessary design data which were hitherto scarce for Nigerian soils are therefore required to accomplish the task effectively. Laboratory investigations were carried out to evaluate angle of soil/material friction and coefficient of soil/ material friction necessary in the design of soil-engaging tools and implements. Facilities used in the investigation include soil-material friction device or sliding shear apparatus. Three types of soil investigated were sandy clay loam soils. The structural materials' surfaces investigated were rubber (RUB), steel (SST), galvanized steel (GAS) and Teflon (TEF). Results show that the coefficient of soil/material friction increased with moisture content to a limit and thereafter decreased. For the materials tested the range was 0.13 -0.85 in the three soil textures and can be described by polynomial equations for the purpose of prediction. Rubber had the highest coefficient of soil/ interface friction followed by smooth steel, galvanized steel, while Teflon had the least in that order.

International Journal of Geo-Engineering

Direct shear experiments were carried out both to investigate the interaction between a predominantly cohesion less soil and in-situ concrete and the validation of the tangent of two-third of the angle of internal friction angle normally assumed in design involving stability of structures with respect to friction. The tests for soil to soil interface indicate internal friction angles of 13.9° and 14.3°, while the soil to in situ concrete interface indicates friction angles of 24.9° and 27.9°. For the soil-concrete interface; the tangent of two-third of the friction angles gives values that are developed by a range of normal stress indicated by the direct shear experiment. These values are between 141 and 430 kPa. The friction values computed from the soil-concrete interface are very conservative for this range of normal stress. However for normal stress values less than 141 kPa, the use of the tangent of two-third of the angle of internal friction principle may not be safe as it may overestimate the friction values which such a system will develop. The study indicates that a range of stress level should be specified for a given friction value adopted in a design situation.

Istraživanja i projektovanja za privredu, 2019

The foundation is an underground construction that functions to deliver loads to the ground. The foundation is used in unfavorable soil conditions where hard soils are found to be very deep. In Supporting the load above it, the pile foundation behavior relies on end bearing, friction resistance and combined end bearing and friction resistance. There are several factors that infl uence the behavior of the pile in supporting the load, namely the type of soil and the method of mounting the pile (put or drilled). At the piles that are located on cohesive soil and the bearing capacity is less profi table, the pile behavior relies on pile friction resistance. As for the pile mounting method in cohesive soils, it will usually result in a rise in ground level around the pile, followed by soil consolidation. To minimize the increase in surrounding soil, the drill is made fi rst, and the precast pile is inserted into the drill hole without being fi xed. In the implementation of the drilling method, the diameter of the hole is made larger than the diameter of the pile, so there is no bond between the pile and the surrounding soil. To fi ll the empty part of the drill hole, additional material is needed which is binding to the surrounding soil. This additional material is expected to be able to produce a pile resistance friction force against vertical loads. Additives used as ingredients added to this study are epoxy and cement resins which aim to increase friction resistance. This study examines the increase in friction resistance values on the soil and pile interfaces using direct shear. The test results show that the highest friction resistance values occur in the mixture with the proportion of soil: epoxy: cement is 62.5%: 25%: 12.5% with addition of 220 ml of water which is 1.1 kg / cm2 at 7 days curing time.

It is well known that soil friction parameters have a significant effect on the overall performance of reinforced soil structures. Since the Coefficient of Friction of the soil is a function of these parameters, it was desired to further investigate the Coefficient of Friction of soil/geotextile interfaces and its relation to the tensile strength of the geotextile used. Accordingly shear box tests were performed inside the laboratory using two soils; organic clay and sandy fill along with four geotextiles that have different tensile strengths to determine the cohesion and internal angle of friction of the soil/geotextile interfaces. These would be used to plot the Coefficient of Friction of these interfaces. It appears from the results of the shear box tests that the Coefficient of Friction of geotextile/organic clay interfaces reduces with the increase of normal stress and increases with the increase of the geotextile tensile strength. However geotextile tensile strength did not seem to have any significant effect on the Coefficient of Friction of geotextile/fill interfaces.

IRJET, 2023

This research is based on to investigating the shear strength interface between concrete and different soil layers like (Clay, Sand and lime mix with other soil), which is very important to ensure the safety and stability of geotechnical engineering structures. Deep foundations like pile and retaining walls heavily rely on the shear strength between these materials to withstand external loads and environmental conditions. In this paper, several types of soils including clay, sand and lime-treated clay are study to know their effect on the shear strength interface. Experimental trials and numerical simulations are supervised to analyze the behavior of the interface under different moisture content conditions. Components like, fine content, sand content, clay content, and moisture content are studied to obtain their impact on shear strength. The results gained give valuable insights into the behavior of the concrete-soil interface and its vulnerability to these factors. The findings of this research identify the important of comprehension the shear strength properties of the concrete-soil interface for designing and constructing safe structures. By identifying the crucial elements affect shear strength, designers and engineers can make decisions concerning material selection, construction techniques, and structural strength analysis. This research adds to the field of geotechnical engineering by increasing knowledge on the shear strength behavior of the Pile foundation concrete-soil interface. The findings can be utilized to increase the design and construction elements, ultimately leading to stable and more efficient civil engineering structures