8 results ·
● Live web index
E
etasr.com
article
https://www.etasr.com/index.php/ETASR/article/download/5842/3109
aimed to design a geotextile-reinforced slope for a target FoS (FoST), using the following steps: Checking unreinforced stability of the final slope configuration to determine the zone of soil contributing to failure and likely to be dislodged from the original soil mass. FHWA recommends values for sliding, local squeezing/bearing capacity failure, and deep-seated stability. Checking the estimated tensile strength of soil reinforcement to achieve the desired FoS with the design chart data [...] TABLE VIII. CALCULATION OF DEEP-SEATED FAILURE SURFACES Type LT (m) LB (m) FOS Valid slip surface Run time (s) Static 5.2 7.8 1.99 3407 8.38 Seismic 4.8 NA 1.71 3407 8.32 Fig. 5. Deep-seated slope stability check. G. Design Summary The final design summary results of the geotextile-reinforced slope include the following specifications: Numbers of geotextile layers: For this problem, N=12 geotextile layers are sufficient. Length of the geotextile layer to be provided at the top surface LT: [...] of the reinforced slope, FoSUN is the FoS of the unreinforced slope, MD is the disturbing moment trying to cause rotational failure, and D is the moment arm about the center of rotation. Figure 2 shows the general configuration of a geotextile-reinforced slope with embedment length Le. The minimum FoS, FoSmin, the FoS corresponding to a maximum value of Tmax, and the maximum value of tensile force in geotextile reinforcement can be calculated for the target FoST. The horizontal distance from
L
library.geosyntheticssociety.org
article
https://library.geosyntheticssociety.org/wp-content/uploads/resources/proceed…
following problem: Determine the factor of safety of a reinforced and unreinforced sandy soil slope with β=50°, γ=16.5 kN/m3, c’=1 kPa, ϕ’=33°, and H=3 m 4.1 Solution It is first required to calculate the stability number, N=c’/γHtan ϕ’ . For this case N=0.03. Using the calculated N value and the stability charts presented in Figure 3 (a-b), the factors of safety for the unreinforced and reinforce slopes are calculated to be 0.85 and 1.25, respectively. It is shown in this analysis that [...] by Zonberg et al. (1998) and Tiwari and Samadhiya (2016) for reinforced slopes, a parametric study was carried out on the 40°, 50°, and 60° slopes (unreinforced and reinforced) as presented in Figure 2 (a-d) by varying the slope soil strength parameters (c’ from 0 to 5 kPa and ϕ’ from 30° to 50°), while keeping the slope height, geosynthetic layout and soil unit weight constant, to determine their effect on the factor of safety, F. The range of c’ and ϕ’ adopted in the study are typical of [...] strength parameters of the slope soil, and γ and H are unit weight of soil and slope height, respectively. (a) (b) Figure 3. Typical design chart: (a) 50° unreinforced slope; (b) 50° reinforced slope. It is observed that F improves with an increase in N and ϕ’ values in both unreinforced and reinforced slope irrespective of the slope angle. It is further noticed that for a constant value of ϕ’, N increases with increasing c’ and for a fixed value of c’, N decreases with an increase in ϕ’. The
L
library.ctr.utexas.edu
research
https://library.ctr.utexas.edu/hostedpdfs/tsusm/0-6792-1.pdf
(K) from Figure 18 and the total design tension: ϕf = [tan-1 × (tanϕr / FSR)] TS-MAX = 0.5 × K × γr × (Hʹ)2 where: ϕf = maximum internal friction angle. ϕr = internal friction angle of reinforced soil. FSR = target minimum reinforced slope factor of safety. TS-MAX = total design tension. K = earth pressure coefficient. γr = unit weight of reinforced soil. Hʹ = apparent height of the slope [H + (q / γr)]. q = uniform surcharge load. To determine the distribution of reinforcement for slopes with [...] soil. Ds = depth of soft soil beneath slope base. θ = angle of slope. H = height of slope. 33 Caution is advised and rigorous analysis (numerical modeling) should be performed when FSsqueezing < 2. This approach is somewhat conservative as it does not provide any influence from the reinforcement. When the depth of the soft layer (DS) is greater than the slope base width (bʹ), general slope stability will govern design. Step 8: Check Seismic Stability To determine dynamic stability, perform a [...] recommended the use of geogrid or a combination of geogrid and geotextile for slope reinforcement, while the others recommended independent use of geotextile. Some prefer high strength geotextiles over geogrids, as they provide a separation function and can be more cost effective in certain cases. Figure 2. Recommended Design Methods. The internal stability of a soil slope can be determined by four basic factors, including the slope angle (β), soil weight (W), cohesion (c), and internal
C
calhoun.nps.edu
research
https://calhoun.nps.edu/bitstream/handle/10945/28542/slopereinforceme00sets.pdf
by DM Setser · 1990 · Cited by 1 — Figure 2.50 gives details of this situation, which results in the following equation. cR + 2 T,y, FS = 1 = 1 OK; adequate safety . Assume that the transfer
S
scdot.org
article
https://www.scdot.org/content/dam/scdot-legacy/business/pdf/geotech/2022-by-c…
(e.g., wire mesh reinforcement) to account for normal stress increase on adjacent soil (see Figure D-7) = Vertical distance, Y, to the centroid of TS for discrete element, strip type reinforcement. Assume H/3 above slope base for preliminary calculations (i.e., assumed to act in a horizontal plane intersecting the failure surface at H/3 above the slope base) (see Figure D-7) 1/φr = Target minimum slope resistance factor which is applied to both the soil and reinforcement 1/φu = Unreinforced [...] of the reinforced slope by: 𝝀𝝀= 𝒅𝒅∗𝜸𝜸𝒘𝒘∗𝒔𝒔 Equation D-29 Where, λ = Tractive shear stress, psf d = Depth of water flow, ft γw = Unit weight of water, pcf Geotechnical Design Manual APPENDIX D January 2022 D-31 s = The vertical to horizontal angle of slope face, ft/ft For λ < 2 psf, consider vegetation with temporary or permanent erosion control mat. For λ > 2 psf, consider vegetation with permanent erosion control mat or other armor type systems (e.g., riprap, gunite, prefabricated modular [...] by reducing the cross-sectional area of the reinforcement used in the design calculations by the anticipated corrosion (see next Section) losses over the design life period as follows: 𝑬𝑬𝒄𝒄= 𝑬𝑬𝒏𝒏− 𝑬𝑬𝑹𝑹 Equation D-1 Where, Ec = Thickness of the reinforcement at the end of the design life En = Nominal thickness at construction ER = Sacrificial thickness of metal expected to be lost by uniform corrosion during the service life of the structure The nominal long-term design strength of inextensible
S
sciencedirect.com
article
https://www.sciencedirect.com/science/article/pii/S0266114417301024
by AH Abd · 2017 · Cited by 130 — Currently, geosynthetic reinforcements for slopes are calculated assuming the ground strength to be purely frictional, i.e. without any cohesion.
C
cdn.glenraven.net
article
https://cdn.glenraven.net/geogrid/pdf/en_us/StrataSlope_Reinforced-soil-slope…
primary geogrid should be chosen. Alternatively, if the calculations yield geogrid spacing greater than 4 feet, a lighter geogrid can be selected. To determine the appropriate geogrid, calculate the long-term design strength (LTDS) of the material as follows: D ID CR ult RF RF RF T LTDS × × = where: Tult = ultimate tensile strength of the reinforcement as per ASTM D6637, RFCR = reduction factor due to creep, RFID = reduction factor due to installation damage, and RFD = reduction factor due to [...] with each other, or with other types of geosynthetically reinforced soil structures such as retaining walls. Designed properly, these soil structures will provide the designer, contractor, and owner with a cost-effective means to build grade separation structures. Example Calculation ________________________________________________________________________ © Copyright 2010 by Strata Systems, Inc. Page 27 Version 100119 Example No. 1. Reinforced Steep Slope Given: The 45-degree slope as shown [...] requirements. At this point in the analysis, the designer must choose a geogrid so that the resulting spacing calculations yield acceptable values. For example, the spacing of primary geogrid layers at the bottom of a slope should not be less than 8 inches to 12 inches. This corresponds to typical earthwork fill thickness. Conversely, the primary geogrid spacing should be no greater than 4 feet. If calculations yield geogrid spacing less than the practical limit, then a stronger primary geogrid
S
solmax.com
article
https://www.solmax.com/ca/en/blog/what-are-the-key-considerations-in-designin…
### Design principles of reinforced soil slopes
The design of reinforced soil slopes hinges on two critical components: the facing system and the reinforcement strategy. The facing system is integral to erosion protection and structural support, enabling the formation of slopes that surpass natural stable inclinations without compromising stability. Secondary reinforcement, typically comprising geosynthetic materials, aids in compaction and mitigates surficial sloughing at the slope face. [...] Reinforced slopes that are 1(H): 1(V) and steeper typically require additional facing support during construction. A geosynthetic face wrap and/or a hard armor facing support system is often employed in these scenarios. Particularly when constructing slopes with materials like silts and poorly graded sands and gravels, or in environments subjected to external erosive forces such as mild water currents and/or wave attack, robust facing supports are essential. Temporary supports such as wooden [...] Geosynthetic materials, including geotextiles and geogrids, play a versatile role in RSS, enhancing structural support, facilitating drainage, and supporting vegetation growth. These synthetic solutions bridge the gap between soft and hard facing options for reinforced slopes, offering tailored reinforcement that meets specific site requirements. They are particularly valuable in environments subjected to dynamic weather conditions and hydraulic pressures, where traditional materials might fail