Design Procedure and Considerations for Piers in Expansive Soils

Nelson, John D.; Thompson, Erik G.; Schaut, Robert W.; Chao, Kaunglin; Overton, Daniel D.; Dunham-Friel, Jesse S.

doi:10.1061/(asce)gt.1943-5606.0000647

Cited by 14 publications

(2 citation statements)

References 12 publications

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“…2 Geofluids effectively confining the horizontal swelling of the soil within acceptable boundaries. The embedded pile in the expansive soil is comparable to the idea of floating piles that Nelson et al (2012) introduced and that Liu and Vanapalli further explored [29,30]. Consequently, the distribution of axial force in the pile, the heave of the soil, and the displacement of the pile will be recorded.…”

Section: Infiltrationmentioning

confidence: 94%

Experimental and Numerical Simulation Study of Water Infiltration Impact on Soil-Pile Interaction in Expansive Soil

Awadalseed,

Zhang,

et al. 2024

Geofluids

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A laboratory model of a single pile embedded in Nanyang expansive soil and subjected to water infiltration is applied in this study to examine the interaction between the expansive soil and pile foundation upon water infiltration. The soil matric suction decreases as a result of the rising soil-water content. The amount of soil ground heave reaches its peak of 10.7 mm after 200 hours of water infiltration. As matric suction decreases, pile shaft friction also declines, which causes more of the load at the pile head to be carried by the pile base resulting in more pile settlements. A new numerical simulation method is provided to simulate this issue by coupling the subsurface flow, soil deformation, and hygroscopic swelling to investigate the expansive soil-pile response upon water infiltration. From the numerical simulation model, hygroscopic strain arises as a result of elevated moisture levels resulting from the entry of water, and due to ground heave and the mobilization of lateral soil swelling, the shear stress at the interface between the soil and the pile gradually increases over time. It reaches its maximum value of 4420 Pa at upper depths around 200 hours after the infiltration. The comparison between the lab model testing data and the numerical model results demonstrates a good level of concurrence.

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Section: Infiltrationmentioning

confidence: 94%

Experimental and Numerical Simulation Study of Water Infiltration Impact on Soil-Pile Interaction in Expansive Soil

Awadalseed,

Zhang,

et al. 2024

Geofluids

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“…Conventional treatment methods include chemically stabilizing the soil, creating horizontal and/or vertical moisture barriers, and adopting special footing systems, such as shallow reinforced concrete rafts and deep concrete piers. However, they all have the following drawbacks: (i) chemical stabilization is time-consuming and only applicable to the top layers of certain soil types [3], (ii) moisture barriers need to be placed at depths greater than the root zone and are ineffective in cracked soils, tight subgrade soils and semi-arid climates [4], (iii) stiffened rafts appear satisfactory only for sites exhibiting low to moderate expansive potential with a shallow active zone [5], and (iv) pier foundations are prone to tension cracks due to swelling induced tensile forces, deep-seated heave and mushrooming due to reckless construction [6][7][8]. Accordingly, a demand for alternative techniques capable of reducing expansive soil induced movement more effectively is evident.…”

Section: Introductionmentioning

confidence: 99%

Performance of driven battered mini-pile group against expansive soil induced ground movement

et al. 2020

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Swell-shrink movement of expansive soils due to seasonal wetting and drying can cause differential ground movements. This movement can inflict substantial structural damage above foundation level to lightly loaded infrastructure. To reduce this movement, techniques have been employed to either (i) chemically restrain the soil’s reactivity, (ii) control the moisture variation within the ground, or (iii) engage a footing system that can limit the impact of the stresses generated by such differential ground movements. Recently, a new concrete-free footing system has been developed in Australia in an attempt to sufficiently resist such ground movements. This system is comprised of an adjustable steel plate attached to the ground by multiple thin steel (hollow) battered mini-piles. The technology shows promise as a low-impact, cost-effective, excavation and concrete-free, innovative alternative to traditional footing systems. It is also quick and easy to install without the use of bulky and expensive equipment. Early field trial results have indicated that this new footing system can combat against and significantly reduce the transfer of the swell-shrink ground movements to a structure. This paper will describe this new footing system and report on an experimental field trial to date, which will include measured ground movements, moisture content and soil suction results vs. depth, as well as the performance of this new driven battered mini-pile group footing system.

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