Experimental study on the strength of silty soft soil in beach with polypropylene fiber reinforcement

2020 ◽  
pp. 10-17
Author(s):  
Qi Daozheng ◽  
Gu Cong ◽  
Fu Jiajia ◽  
Wang Yao
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Shear Strength ◽  
Internal Friction ◽  
Unconfined Compressive Strength ◽  
Fiber Length ◽  
Soft Soil ◽  
Polypropylene Fiber ◽  
Fiber Reinforcement ◽  
Fiber Content

The effects of polypropylene fiber reinforcement on shear strength and unconfined compressive strength of silty soft soil in tidal flats were studied. Through shear test and unconfined compression test, Experimental study was conducted on silty soft soil of allene fiber reinforced beach with 0~0.6% different mass content and 3 ~18m different length. The failure process and mechanism of fiber reinforced soil samples were also discussed. The test results show that: Shear strength (cohesion and internal friction Angle) and unconfined compressive strength increased rapidly in the early stage with the increase of fiber content, and gradually decreased after reaching the peak at a certain content. In this test, the optimal fiber length corresponding to shear strength is 9mm. When the content is less than 0.6%, the optimal content of cohesion is about 0.2%, and the optimal content corresponding to the Angle of internal friction is between 0.2% and 0.3%. Within the range of 18mm fiber length in the experimental study, unconfined compressive strength increased with the increase of fiber length, and the optimal fiber content corresponding to unconfined compressive strength was 0.2%. The main effects of polypropylene fiber reinforcement on soil cohesion and unconfined compressive strength are not obvious.

scholarly journals Experimental Study on Improvement of Marine Soft Soil with Alkali Residue

2018 ◽  
Vol 53 ◽  
pp. 04021
Author(s):  
SHAO Yong ◽  
LIU Xiao-li ◽  
ZHU Jin-jun
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Void Ratio ◽  
Soft Soil ◽  
Compressive Modulus ◽  
Engineering Properties ◽  
Test Results ◽  
Use Of Resources ◽  
One Year

Industrial alkali slag is the discharge waste in the process of alkali production. About one million tons of alkali slag is discharged in China in one year. It is a burden on the environment, whether it is directly stacked or discharged into the sea. If we can realize the use of resources, it is a multi-pronged move, so alkali slag is used to improve solidified marine soft soil in this paper. The test results show that the alkali residue can effectively improve the engineering properties of marine soft soil. Among them, the unconfined compressive strength and compressive modulus are increased by about 10 times, and the void ratio and plasticity index can all reach the level of general clay. It shows that alkali slag has the potential to improve marine soft soil and can be popularized in engineering.

Research about the Effect of Polypropylene Fiber on Mechanical Properties of Curing Sludge

2011 ◽  
Vol 250-253 ◽  
pp. 788-794
Author(s):  
Shu Lin Zhan ◽  
Shu Sen Gao ◽  
Jun Ying Lai
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Shear Strength ◽  
Water Content ◽  
Unconfined Compressive Strength ◽  
Polypropylene Fiber ◽  
Physical And Mechanical Properties ◽  
Curing Time ◽  
Strength Tests ◽  
Different Content

In order to study the influence of modified polypropylene (PP) fiber on the physical and mechanical properties of curing sludge, the same amount of cement and different content of polypropylene fiber were mixed into the sludge. Unconfined compressive strength tests, water content tests and shear strength tests were carried out on different specimens with different curing time. The results show that the sludge curing effect is markedly improved by the addition of the polypropylene fiber. As to the curing sludge with the same curing time, when the content of the polypropylene fiber increases, the unconfined compressive strength and the cohesive strength greatly increase, and the internal frictional angle decreases.

scholarly journals Study on Mechanical Properties of Basalt Fiber-Reinforced Concrete with High Content of Stone Powder at High Temperatures

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lina Xu ◽  
Daohan Song ◽  
Ning Liu ◽  
Wei Tian
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Temperature ◽  
Unconfined Compressive Strength ◽  
Fiber Length ◽  
Basalt Fiber ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Acoustic Response

Concrete materials are an important part of global structure, and their fire resistance directly affects the safety of buildings and tunnels. In this study, basalt fiber was used to reinforce concrete with high content of stone powder in order to enhance its high-temperature performance. The mechanical properties and ultrasonic characteristics at different temperatures were studied using the cube compressive strength test and nonlinear ultrasonic test. The results indicated that the addition of basalt fiber in specimens improved their compressive strength; however, this strength did not continuously increase with increases in the fiber length and fiber content, and the optimal values for fiber length and fiber content were determined to be 12 mm and 1 kg/m3 at 600°C, respectively. With increases in temperature, the unconfined compressive strength increased first and then decreased. When the temperature was 400°C, the unconfined compressive strength of the specimens reached their highest values and then decreased. When the temperature was 400°C and 600°C, the strength of the stone powder concrete with fiber was higher than that without fiber, which shows that fiber can improve the mechanical properties of concrete at high temperatures. Based on the Box-Behnken design (BBD) method, the unconfined compressive strength response regression model of basalt fiber-reinforced concrete with high content of stone powder, which follows parameters including fiber content, fiber length, and temperature at high-temperature environments, was established, and it was found that the interaction of fiber content, fiber length, and the temperature was significant based on multifactor interaction analysis. The analysis of ultrasonic signals based on the S transform showed that, with increases in temperature, the amplitudes of the acoustic response signals, the corresponding frequency spectrum, and the time-frequency spectrum were clearly reduced. At the same temperature, the amplitudes of the acoustic response signals of different concrete testing blocks did not change much and remained at the same level.

scholarly journals COMPARISON OF THE BEHAVIOR OF FIBER AND MESH REINFORCED SOILS

2017 ◽  
Vol 8 (2) ◽  
pp. 82-88
Author(s):  
Y. C. Fung ◽  
Shenbaga. R. Kaniraj
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Unconfined Compressive Strength ◽  
Failure Strain ◽  
Soft Soil ◽  
Soil Samples ◽  
Soil Reinforcement ◽  
High Plasticity ◽  
Soil Matrix ◽  
Treated Soil

Soft soil does not have good soil properties and is not suitable for constructing pavement structures as shear strength is required to resist the shear stress developed by traffic loading. To increase shear strength in this study, lime is used as the soil stabilizing agent and fiber and mesh are used as the soil reinforcement materials. The proper amount of lime added to soil will increase the shear strength as the lime-treated soil will decrease moisture susceptibility and migration. Shear strength of the lime-treated soil can be further improved by adding reinforcement materials such as fiber and mesh. The reinforcement materials will interlock with groups of particles and provide tensile strength to the soil matrix. The type of soil used in this study is high plasticity elastic silt with sand which is classified using the Unified Soil Classification System (USCS). Quicklime (calcium oxide) is used in this study at the minimum amount required for stabilizing the soil, which is 9%. The amount of fiber and mesh added to the soil sample is 0.5% of the dry weight of the soil used. Cylindrical samples were prepared with a moisture content of 22% (OMC) for untreated soil and 21% (OMC) for lime-treated soil samples. The lime-treated soil samples were cured for 7, 14, 28, 56, 90 and 120 days. Unconfined compression tests were conducted to determine unconfined compressive strength (UCS) and stress-strain characteristics. The unconfined compressive strength of the lime-treated samples increased as curing period increased but the failure strain decreased. The UCS and failure strain for reinforced lime-treated soil samples are higher than the unreinforced lime-treated soil samples.

scholarly journals Stability Analysis of Soil Embankment Slope Reinforced with Polypropylene Fiber under Freeze-Thaw Cycles

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yafeng Gong ◽  
Yulong He ◽  
Chunpeng Han ◽  
Yangfan Shen ◽  
Guojin Tan
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Finite Element Model ◽  
Fiber Length ◽  
Polypropylene Fiber ◽  
Element Model ◽  
Fiber Content ◽  
Freeze Thaw ◽  
Embankment Slope ◽  
The Finite Element Model

Polypropylene fiber is a common soil reinforcement material which is used to reinforce a common clay in northeast China. Numerical analysis method was performed to investigate the effect of polypropylene fibers on stability of embankment slope subjected to freeze-thaw cycles. The orthogonal experiments of three factors (freeze-thaw cycle, fiber content, and fiber length) and three levels were carried out, and the corresponding nine groups of specimens were made, whose shear strength parameters (internal friction angle and bond force) were measured by direct shear test. Then, the experimental results were analyzed by analysis of variance and range analysis so that the optimum fiber content and fiber length can be determined. The finite element model of typical high-fill soil slope of freeway in northeast China was established whose basic material parameters were taken as the parameters of shear strength of different freeze-thaw cycles under the optimum fiber content and fiber length. The concept of shear strength reduction was introduced into the finite element model, and the convergence of the finite element model was taken as the judging criterion of slope stability. Thus, stability analysis of soil embankment slope reinforced with polypropylene fiber under freeze-thaw cycles was realized. The results show that the addition of fibers improves the cohesion under the action of freeze-thaw cycles, and the internal friction angle is improved in the case of freezing and thawing. This phenomenon leads to the improvement of the stability of the embankment slope in a freeze-thaw cycle. The improvement is particularly noticeable in the case, and this improvement effect decreases as the number of freeze-thaw cycles increases.

scholarly journals Influences of Curing Environment on Strength Performances of Shanghai Clayey Soil Reinforced with Palm Fiber

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jili Qu ◽  
Kun Xiong
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Internal Friction ◽  
Shear Modulus ◽  
Unconfined Compressive Strength ◽  
Clayey Soil ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Curing Conditions ◽  
Palm Fiber

Owing to its environment-friendly, economically available, and sustainable property, the palm fiber was attempted to improve the quality of Shanghai clayey soil together with lime. The direct shear tests (DST), ultrasonic pulse velocity tests (UPV), and the unconfined compressive tests (UCT) have been carried out on soils mixed with palm fiber and lime under 3 curing conditions of immersion in water, cyclic wetting-drying, and air curing at a series of contents of additives. The corresponding indexes of shear strength (τ), cohesion (c), internal friction angle (φ), initial shear modulus (G0), and unconfined compressive strength (qu) were obtained and analyzed. Results show that immersed-in-water environment is optimum for the formation of shear strength, initial shear modulus, cohesion, and unconfined compressive strength (UCS), while the air curing condition is the worst for admixture treated soil. Lime can increase G0, but palm fiber can slightly reduce G0. Lime has significant effect on increase of internal friction angle; on the contrary, palm fiber has only limited effect. c/G0 for any type of sample remains almost constant under different curing conditions. It demonstrates that c and G0 possess the comparative development trend under different curing environment.

Experimental Study on Strength and AE Characteristics for PFRC with Different Fiber Content

2012 ◽  
Vol 446-449 ◽  
pp. 297-302
Author(s):  
Yao Wang ◽  
Yan Wang ◽  
Wei Hong Xuan ◽  
Gang Zheng ◽  
Yu Zhi Chen
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fiber Diameter ◽  
Polypropylene Fiber ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Test Results ◽  
Action Mechanism ◽  
Polypropylene Fiber Reinforced Concrete

Tests for compressive strength and splitting tensile strength were performed on the concrete reinforced by Polypropylene Fiber of two diameters and of three fiber contents respectively and the whole loading process was monitored by acoustic emission (AE) technique. The test results showed that compressive strengths of Polypropylene Fiber Reinforced Concrete (PFRC) changed slightly with the increasing of fiber content but that splitting strengths changed more. The change rule of splitting strengths with fiber content was related to Fiber diameter which would determine a certain average fiber distance in concrete. There existed a bound value of average fiber distance, which was the most favorable to the splitting strength. Nine AE parameters of specimens received from their splitting tests always showed maximum or minimum at a fiber content of 0.6 kg/m3, which meant that these parameters would be helpful to the further research for the action mechanism of fiber in concrete.

Experimental Study of the Relationship between Matric Suction and Strength of Unsaturated Residual Clay in Xiamen under Different Drying-Wetting Cycle Paths

2013 ◽  
Vol 838-841 ◽  
pp. 680-684
Author(s):  
Dong Xia Chen ◽  
Ming Xin Meng ◽  
Ji Wei Luo
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Internal Friction ◽  
Unconfined Compressive Strength ◽  
Characteristic Curve ◽  
Friction Angle ◽  
Matric Suction ◽  
Internal Friction Angle ◽  
The Relationship ◽  
Cycle Path

To discuss the relationship between matric suction and strength under different drying-wetting cycle paths of residual clay, soil water characteristic curve was determined by the filter paper method. The shear strength, unconfined compressive strength and matric suction were obtained during desorption and adsorption at the drying and wetting cycle. The experimental results show that the matric suction of soil specimens subjected to different drying and wetting cycle paths are different although at the same water content. Contributions of internal friction angle and cohesion to shear strength are different at different matric suction. In the low matric suction stage, matric suction mainly contribute to shear strength by affecting the cohesion, yet in the high matric suction stage by increasing both the internal friction angle and cohesion; in the transition matric suction stage, the contribution of cohesion decreases while the contribution of internal friction angle increases. Furthermore, the unconfined compressive strength of specimens subjected to the drying and wetting cycle path of desorption first and then adsorption is reduced and increase with the opposite path.

Effect of Clay Dosage on Mechanical Properties of Plastic Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 664-667 ◽  
Author(s):  
Qiao Yan Guan ◽  
Peng Zhang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Elastic Modulus ◽  
Internal Friction ◽  
Friction Angle ◽  
Splitting Tensile Strength ◽  
Plastic Concrete

A designed experimental study has been conducted to investigate the effect of clay dosage on mechanical properties of plastic concrete. The mechanical properties include compressive strength, splitting tensile strength, shear strength and elastic modulus. On the basis of the experimental results of the specimens of eight sets of mix proportions, the mechanism of action of clay on these mechanical properties has been analyzed in details. The results indicate that there is a tendency of decrease in the compressive strength, splitting tensile strength, shear strength and elastic modulus of plastic concrete with the increase of clay dosage. However, the internal friction angle of the shear specimens is increasing gradually with the increase of clay dosage. Further, the clay appears can improve the ductility of plastic concrete and this can help plastic concrete to bear larger deformation before failure.

Sign in / Sign up

Export Citation Format

Share Document