Geotechnical engineering practice for collapsible soils

Houston, Sandra L.; Houston, William N.; Zapata, Claudia E.; Lawrence, Chris

doi:10.1007/978-94-015-9775-3_6

Cited by 47 publications

(43 citation statements)

References 7 publications

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“…This was interpreted as a fast sand contraction (volume reduction in loose materials under reduced drainage) with pore water being expelled from the watersaturated pores generating pore water pressure. Collapse upon wetting is typical of very loose granular soils when wetted for the first time (Houston et al, 2001).…”

Section: Wettable Sand (Strong) Mixturementioning

confidence: 99%

Processes in model slopes made of mixtures of wettable and water repellent sand: Implications for the initiation of debris flows in dry slopes

Lourenço

Wang

Kamai

2015

Engineering Geology

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a b s t r a c tDebris flows in slopes initially dry, such as post-wildfire debris flows, are initiated by surface runoff and sediment bulking due to reduced infiltration. Soil water repellency, extreme dry soils, and loose, cohesionless materials influence their initiation. The exact link between these features, the resulting infiltration processes and the initiation mechanism of a debris flow remains unclear. Here, we examine the relation between soil particle wettability and slope processes in physical models. Flume experiments were conducted in 10% increments of mass ratios of wettable to water repellent sand, subjected to artificial rainfall with monitoring of soil water content, pore water pressure, sediment and water discharge and failure mode. To date, wettability was considered only for the water repellent end, because it reduces infiltration, enhancing surface runoff. This study demonstrates that slight wettability changes, in the full wettable to water repellent range, impact a variety of slope processes. The two extremes, fully wettable and water repellent gave opposite responses, retrogressive slides for infiltrationinitiated in wettable sand and erosion by surface runoff in water repellent sand. The transition was dominated by surface runoff and preferential flow, yielding a combination of erosion and slides. From the tests, a continuous capping effect generated by water repellency was a necessary condition for erosion and sand bulking i.e., the generation of runoff-initiated debris flows. The sensitivity of the model slope response to artificial rainfall was particularly acute at high ratios of wettable to water repellent sand. For mixtures above a critical ratio of wettable to water repellent sand, the measurements with an index test revealed a fully wettable material despite differences in the infiltration, saturation and pore water pressure built-up trends. Implications for post-wildfire debris flows and debris flows in slopes initially dry in general are discussed.

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Section: Wettable Sand (Strong) Mixturementioning

confidence: 99%

Processes in model slopes made of mixtures of wettable and water repellent sand: Implications for the initiation of debris flows in dry slopes

Lourenço

Wang

Kamai

2015

Engineering Geology

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“…In semi-arid New Mexico, a commercial building won an award from the city for the year's most beautiful lawn and landscaping. However, it suffered in foundation damage owing to 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 differential settlement due to wetting of collapsible foundation soils underneath (Houston et al, 2001). …”

Section: Collapsible Soilsmentioning

confidence: 99%

Geotechnical case studies: emphasis on collapsible soil cases

Vandanapu

Omer

Attom

2016

Proceedings of the Institution of Civil Engineers - Forensic En

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Direct exposure of soil to certain atmospheric agents, such as water, can influence adversely or favourably the engineering behaviour of the soil. For instance, saturated and unsaturated/partially saturated soils behave differently, so do soils under seepage and hydrostatic pressures. Many theories in soil mechanics idealise soils as either cohesive or non-cohesive, and this has allowed much research to be done on saturated cohesive soils. However, non-cohesive soils have not received as much attention, apart from recent strength and dilatancy theories, yet in some parts of the world, certain non-cohesive soils pose significant risk to structures built on them. The most problematic examples of such soils are collapsible soils that may not be detected and properly considered in routine ground investigation activities. In this paper some case studies of collapsible soils in the United Arab Emirates are examined to analyse the effect of their collapse on infrastructure and the possible techniques to ameliorate the situation. The case studies include various sites that were found to suffer structural damage traceable to collapsible soils. It is found that in most cases the soil collapse was due to infiltration of rainwater or water from sustained irrigation activities at the surface.

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“…In fact, according to Clemence and Finbarr (1981), Rogers (1995), Lin (1995), Bell and De Bruyn (1997), and Houston et al (2001Houston et al ( , 2003, a sudden and significant volume reduction occurs when the material undergoes a water content increase, not necessarily just in the presence of increased stress.…”

Section: Introductionmentioning

confidence: 99%

The open metastable structure of a collapsible sand: fabric and bonding

Zimbardo

Ercoli

Megna

2015

Bull Eng Geol Environ

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This paper deals with the compositional and textural characteristics determining open metastable structures in the pleistocenic sand outcropping in the Agrigento district (Sicily). The aim of the study was to individuate the bonding types occurring between grains that could generate matric suction phenomena. The composition and microfabric were characterised by means of granulometry, porosimetry, permeability, optical and ESEM-EDS microscopy, thermogravimetry and XR diffractometry, electric conductivity, and ionic chromatography. The data thus acquired show that the skeleton of the sand is constituted mostly by bioclasts and microfossils, calcite and quartz monocrystalline grains. Moreover, assemblages of silt and clay minerals are interposed among them. Cementation is generally absent even at the sites of contact between grains. Porosity is due mainly to interparticle voids. The spatial arrangement of sand, silt and limey grains, the pore geometry, volume and size distribution and network connectivity allow both capillary condensation and effective capillary transport of water. It appears that bonding is due mainly to capillary forces related to the texture and to the type of pores rather than being ruled by composition.

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Geotechnical engineering practice for collapsible soils

Cited by 47 publications

References 7 publications

Processes in model slopes made of mixtures of wettable and water repellent sand: Implications for the initiation of debris flows in dry slopes

Processes in model slopes made of mixtures of wettable and water repellent sand: Implications for the initiation of debris flows in dry slopes

Geotechnical case studies: emphasis on collapsible soil cases

The open metastable structure of a collapsible sand: fabric and bonding

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