Experimental study on the soil mixture to promote vegetation for slope protection and landslide prevention

Abstract

Water infiltration is one of the most important triggers of landslides. Vegetation is an effective way to mitigate water infiltration, reduce soil surface cracking, and, consequently, prevent landslides. In recent years, a soil mixture has been successfully used to grow vegetation on steep soil/rock surfaces by hydroseeding or shotcreting. The mixture contains seven ingredients, namely cement, fiber, peat, water retention agent, soil conditioner, soil, and pH adjusting agent. This study includes a germination and growth field test and a series of lab shear strength tests to assess: (1) the influence of the mixture's ingredients on germination and growth of the vegetation and (2) the effect of cement and fiber on the shear strength of the cured mixture. For the germination and growth test, the Taguchi method was utilized to determine the content of each ingredient (i.e., the percentage of each ingredient) used to prepare different mixtures. Cynodon dactylon was planted in different mixtures and the germination and growth had been monitored for 3 months. The results indicated that the cement content had a significant influence on germination whereas the content of peat, soil conditioner, fiber, and water retention agent had a medium to negligible influence on germination. The content of all the ingredients had an influence on the plant's growth and the influence of the cement content was the greatest. When the cement content is higher than 10 %, the growth of the plant is greatly hindered; therefore, to ensure a reasonable growth in the field, the cement content should be less than 10 %. The shear strength tests used the sample prepared with different contents of cement and fiber, but the same porosity. The results showed that the contents of cement and fiber had a negligible influence on the friction angle, and the cohesion increased with the increase of cement content or decrease of the fiber content. Curing time of 7-14 days yielded the maximal cohesion.

A Survey of Multiple Interactions Between Plants and the Urban Environment

“…and Fini (2011), Grote et al (2016), Livesley et al (2016), Maher et al (2013), Mori et al (2016), Pasha et al (2018), Potgieter (2019), Rahman et al (2017), Rey et al (2019), Shanahan et al (2015), Shackleton et al (2015), Tanaka and Onai (2017), Xiao et al (2017), and Weissert et al (2017). c Cavender and Donnelly (2019), Carrus et al (2015), Clément (2004), Fischer and Lindenmayer (2002), Hofmann et al (2018), Luck et al (2011), and Lumsden and Bennett (2005).…”

“…In general, from the environmental point of view, plant benefits include climatic regulation; uptake/reduction of CO 2 and other greenhouse gases and pollutants; shading, which reduces urban heat island effects and is a general cooling factor, also intercepting incoming precipitations and avoiding dangerous water run-off while enriching water-table capacity (Alexandri and Jones, 2008;Edmondson et al, 2012;Maher et al, 2013;Livesley et al, 2016;Mori et al, 2016;Berland et al, 2017;Dobbs et al, 2017;Rahman et al, 2017;Weissert et al, 2017;Andoni and Wonorahardjo, 2018). Plants in densely urbanized areas also contribute to environmental protection from several hazards like strong winds, soil and slope erosion, torrential floods, landslides (Tanaka and Onai, 2017;Xiao et al, 2017;Pasha et al, 2018;Rey et al, 2019), and reduce traffic noise (Carrus et al, 2015;Shackleton et al, 2015). According to several results reviewed by Donovan (2017), benefits provided by plants (note: the author specifically refers to trees) change relative to their location within the urbanized area.…”

Soil and water bioengineering: Practice and research needs for reconciling natural hazard control and ecological restoration

“…Traditionally, a limited number of plant species has been used for this purpose, although there are countless species available that could perform equally well, many of which have not yet been tested for suitability (Preti and Petrone, 2013;Perez et al, 2017). In general, although using pioneering species in soil bioengineering projects is sometimes necessary to initiate the successional processes that will maintain vegetation on the site, native species should be preferred over exotic species and ecological succession trajectories should be included in the bioengineering intervention design (Clemente et al, 2016;Xiao et al, 2017).…”

Thermal Properties of Carbon Fiber-Reinforced Lightweight Substrate for Ecological Slope Protection

“…Exposed slopes are most prone to water erosion, particularly in areas with a high rainfall, thereby often leading to disastrous landslides [1]. As reported by the U.S. Geological Survey (USGS), thousands of major landslides were triggered by rainfall each year [2]. Over the past decades, various solutions have been proposed to prevent the occurrence of such landslide accidents.…”