We demonstrate a novel experimental arrangement for measuring wind turbulence‐induced gas transport in dry porous media under controlled conditions. This equipment was applied to assess the effect of wind turbulence on gas transport (quantified as a dispersion coefficient) as a function of distance to the surface of the porous medium exposed to wind. Two different strategies for the measurement of wind‐induced gas transport were compared. Experiments were carried out with O ₂ and CO ₂ as tracer gases with average vertical wind speeds of 0.02–1.06 m s ⁻¹ . Oxygen breakthrough curves as a function of distance to the wind‐exposed surface of the porous medium were analysed numerically with a finite‐difference‐based model to assess gas transport. We showed that wind turbulence‐induced gas transport is an important transport mechanism that can be 20–70 times larger than molecular diffusion‐induced transport. Wind conditions and properties of the porous medium had strong controlling effects on this relationship. Importantly, we show that even though wind‐induced gas transport is greatest near to the wind‐exposed surface, it can have marked effects on the variation in gas concentration at much greater depths. Highlights: We explored the effect of atmospheric wind turbulence on gas transport in porous media. We measured the depth relation of wind‐induced dispersion in porous media for real wind conditions. Wind‐induced gas dispersion coefficients were 20–70 times larger than molecular diffusion. Wind turbulence can potentially have a considerable effect on gas transport in porous media.

Microbially Induced Carbonate Precipitation (MICP) is currently viewed as one of the potential prominent processes for field applications towards the prevention of soil erosion, healing cracks in bricks, and groundwater contamination. Typically, the bacteria involved in MICP manipulate their environment leading to calcite precipitation with an enzyme such as urease, causing calcite crystals to form on the surface of grains forming cementation bonds between particles that help in reducing soil permeability and increase overall compressive strength. In this paper, the main focus is to study the MICP performance of three indigenous landfill bacteria against a well-known commercially bought MICP bacteria (Bacillus megaterium) using sand columns. In order to check the viability of the method for potential field conditions, the tests were carried out at slightly less favourable environmental conditions, i.e., at temperatures between 15-17°C and without the addition of urease enzymes. Furthermore, the sand was loose without any compaction to imitate real ground conditions. The results showed that the indigenous bacteria yielded similar permeability reduction (4.79 E-05 to 5.65 E-05) and calcium carbonate formation (14.4–14.7%) to the control bacteria (Bacillus megaterium), which had permeability reduction of 4.56 E-5 and CaCO₃ of 13.6%. Also, reasonably good unconfined compressive strengths (160–258 kPa) were noted for the indigenous bacteria samples (160 kPa). SEM and XRD showed the variation of biocrystals formation mainly detected as Calcite and Vaterite. Overall, all of the indigenous bacteria performed slightly better than the control bacteria in strength, permeability, and CaCO₃ precipitation. In retrospect, this study provides clear evidence that the indigenous bacteria in such environments can provide similar calcite precipitation potential as well-documented bacteria from cell culture banks. Hence, the idea of MICP field application through biostimulation of indigenous bacteria rather than bioaugmentation can become a reality in the near future.

Peat is a very variable but normally weak material. While engineering failures involving peat are common, the full diversity of engineering behaviours exhibited by peat has not been well classified due to its large range of possible compositions. This paper presents the behaviour of a fibrous peat which is a fill (made ground) originating from the most recent dredging of the West Lake, a site of cultural and historic importance in China. Given its relatively unique mechanism of deposition, the distinctive characteristics of this peat are presented in comparison to other peats reported in the literature highlighting its unique engineering behaviour. A laboratory study carried out on the peat at Jiangyangfan Eco-park, located in Hangzhou, China identifies that it has its special aspects when compared to other peats. The shearing behaviour of peat can be described using the framework of critical state theory. The most prominent characteristic of the West Lake Peat is that its undrained stress path bends towards the left at the very beginning of shearing which indicates that plastic deformation occurs at very small stress ratios. A constitutive model based on critical state theory for predicting the undrained shear behaviour of this type of peat from low stress to critical state levels is presented. This model also includes several elements of peat behaviour previously reported and it may therefore be applied to a wider range of peat soils