“…And the optimal content of 19 mm PP fiber is 0.45%. ese contents are consistent with the results of Yadav and Tomar [30,31]. e UCS of PP fiber-reinforced solidified soil varies with varying fiber length.…”
Section: Effects Of Fiber Length and Fiber Content On Ucs And Stssupporting
Urgent repair and construction of airstrips is a research hotspot in global airport engineering. Selecting the proper structural materials is a key component of the airstrip repair process. First, with unconfined compressive strength and splitting tensile strength, the fiber length and content of polypropylene (PP) fiber-reinforced solidified soil were optimized. Then, using a scanning electron microscope, the reinforcing mechanism of PP fiber on soil and the influence mechanism of fiber parameters on fiber-reinforced soil were discussed and analyzed. Lastly, a full-scale test section was paved, on which static and dynamic loading tests were performed to verify the carrying capacity and deformation characteristics of the full-scale test section. The above research provides a theoretical foundation and data support for the urgent repair and construction of airstrip. Results indicate that PP fiber with length of 12 mm and fiber content of 0.3% has optimal performance and economic cost. The reinforcing mechanism of fiber-reinforced soil can be summarized to be the effect of a one-dimensional lacing wire and the effect of a three-dimensional network structure. Fibers show two failure modes of pull-out and tensile failure. After 20000 dynamic loading cycles, the stress at the bottom of each structural section varies less, the graded plastic deformation is stable, and the cumulative plastic deformations of the fiber-reinforced soil base, solidified soil base, and cemented soil base pavement structures are 0.83 mm, 0.93 mm, and 1.2 mm, respectively. Pavement structure composed of fiber-reinforced solidified soil can meet the load capacity requirements for use in airstrips under the characteristics of time-sensitive application.
“…And the optimal content of 19 mm PP fiber is 0.45%. ese contents are consistent with the results of Yadav and Tomar [30,31]. e UCS of PP fiber-reinforced solidified soil varies with varying fiber length.…”
Section: Effects Of Fiber Length and Fiber Content On Ucs And Stssupporting
Urgent repair and construction of airstrips is a research hotspot in global airport engineering. Selecting the proper structural materials is a key component of the airstrip repair process. First, with unconfined compressive strength and splitting tensile strength, the fiber length and content of polypropylene (PP) fiber-reinforced solidified soil were optimized. Then, using a scanning electron microscope, the reinforcing mechanism of PP fiber on soil and the influence mechanism of fiber parameters on fiber-reinforced soil were discussed and analyzed. Lastly, a full-scale test section was paved, on which static and dynamic loading tests were performed to verify the carrying capacity and deformation characteristics of the full-scale test section. The above research provides a theoretical foundation and data support for the urgent repair and construction of airstrip. Results indicate that PP fiber with length of 12 mm and fiber content of 0.3% has optimal performance and economic cost. The reinforcing mechanism of fiber-reinforced soil can be summarized to be the effect of a one-dimensional lacing wire and the effect of a three-dimensional network structure. Fibers show two failure modes of pull-out and tensile failure. After 20000 dynamic loading cycles, the stress at the bottom of each structural section varies less, the graded plastic deformation is stable, and the cumulative plastic deformations of the fiber-reinforced soil base, solidified soil base, and cemented soil base pavement structures are 0.83 mm, 0.93 mm, and 1.2 mm, respectively. Pavement structure composed of fiber-reinforced solidified soil can meet the load capacity requirements for use in airstrips under the characteristics of time-sensitive application.
The COVID-19 pandemic has not only caused a global health crisis, but it has also had significant environmental and human consequences. During the COVID-19 pandemic, this study focused on emerging challenges in managing healthy personal protective materials (HPPM) in Kingdom of Saudi Arabia, using silty sand (SM) soil as an example since it covers large areas in KSA and in the whole world. The main objective of this paper is to find a novel way to minimize pandemic-related waste by using HPPM as waste materials in road construction. For the first time, a series of experiments was conducted on a mixture of different percentages of shredded HPPM (0, 0.5, 1 and 2%) added to the silty sand (SM) soil for road applications, including soil classification according to the USCS, modified compaction, UCS, UPV, and CBR. In addition, a numerical simulation was performed using geotechnical-based software Plaxis 3D to study the performance of the soil-HPPM mix as a subbase layer in the paving structure under heavy traffic loading. The modified compaction test results show that there is an increase in the optimum moisture content with increasing the HPPM contents from 0.5% to 1% and 2%. However, a reduction in the maximum dry density is observed. The values of dry density and water content at 0%, 0.5%, 1% and 2% pf HPPM are 2.045, 1.98, 1.86 and 1.8 g/cm
3
and 7.65% 8%, 8.5% and 9.5%, respectively. The soaked CBR values at 0, 0.5, 1 and 2% HPPM are 23, 30, 8, 2% with the maximum value attained with the addition of 0.5% HPPM. The results of UCS were with the same percentages of HPPM 430, 450, 430 and 415 kPa, respectively, with the maximum value attained with 0.5% HPPM addition as well. In contrast, the values of UVP at 0%, 0.5%, 1% and 2% are 978.5, 680.3, 489.4 and 323.6 m/s, respectively, confirming the trends obtained by modified compaction test results. The simulation results confirm this conclusion that the soil-HPPM mix show a superior performance when used as a subbase layer and reduced vertical displacement by a percentage of 11% compared to the normal subbase material. By eliminating HPPM especially facemasks from the landfill lifecycle, incorporating them into high quality construction material production has the potential to deliver significant environmental benefits.
“…erefore, it could be predicted that the threshold for the experiment must be near the turning point. Consequently, taking 15% as the benchmark, the upper and lower two intervals [5,15,25] were divided in half to selected discrete points (10% and 20%), respectively. en, the interval of the threshold was further narrowed from [5,10,20,25].…”
Section: St Resultsmentioning
confidence: 99%
“…And all of these could be mainly attributed to the good pozzolanic and filling effects of nano-SiO 2 [23,24]. In limited studies, the properties of nano-SiO 2 to improve the mechanical properties of soil have been continuously verified [22,25]. Compared with traditional chemical additives such as cement and lime, the application of nano-SiO 2 in soil improvement greatly reduces the total cost of the stabilizer [26].…”
Frequent occurrence of landslides has seriously threatened the infrastructural projects in the Loess Plateau, China. At the beginning, with development of the landslide, several fissures were generated along the internal weak surface. Then, under the constant influence of rainfall and irrigation, the fissures were expanded and connected, which formed a consecutive sliding surface, consequently leading to the occurrence of the landslide. Therefore, the key to treat the landslide is to prevent the expansion and connection of fissures in the potential slip zone inside the slope. In this paper, an old landslide, which occurred at an early stage of the construction of the Lvliang Airport, was selected as a case study. A new type of grouting material was used to fill the fissures and reinforce the loess in the slip zone, so as to study the effect of material content on the slope stability. With current methods, loess specimens were taken from the slip zone inside the Lvliang Airport slope. Based on the GDS triaxial test system, a series of laboratory tests were performed on the undisturbed loess and the remolded which contained the stabilizer, including triaxial shear tests at constant matric suctions and wetting tests at constant deviator stresses. Moreover, the dichotomy in mathematics was chosen to find the threshold of the material content. The test results showed that the cohesion and the internal friction angle of the loess obviously increased after grouting. The failure behaviour of the loess along the wetting path was dependent on the material ratio and the stress level. Meanwhile, the critical state line of the slope, grouted with materials of different ratios, was compared by fitting the regression equation. It was found that the threshold value of the stabilizer content was between 15% and 20%, which was the most suitable ratio for improving slope stability with relatively lower cost.
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