Biochar is a recalcitrant material obtained after pyrolysis of labile biomass under oxygen-limited condition. The conversion of biomass into biochar is considered to be a sustainable way of generating bioenergy, minimizing the emission of greenhouse gases and managing the waste. Recently, the amendment of biochar in soil gained attention due to its multiple soil ameliorating features. Many studies have investigated the effect of biochar particle size on the physicochemical and hydraulic properties of relatively loose agricultural soil. However, such study is rarely conducted for compacted soil suitable for bioengineered structures. The objective of the current study is to investigate the effect of biochar particle size on the hydraulic conductivity of compacted soil for bioengineered structures. Saturated hydraulic conductivity (K_sat) of different compacted soils amended with biochar of different particle sizes ranging from 0.075 to 4.75 mm has been investigated. The results showed that the amendment of 5% to 15% (w/w) biochar of different particle sizes led to the change in K_sat of the silty sand. When compared with bare soil, a higher K_sat with biochar of particle size larger than 0.425 mm and a lower K_sat with particles of size smaller than 0.425 mm was observed. However, in pure sand, a lower K_sat irrespective of particle size of biochar was observed and the lowest K_sat was noted with biochar of particle size smaller than 150 mm. These changes in the K_sat after biochar amendment were attributed to the alteration of pore structure mainly, inter-pores of the soil, which is controlled by the particle size of the biochar. The findings of the present study could be useful for the field application i.e. in bioengineered structures.

生物炭是在氧气受限的条件下将不稳定的生物质热解后获得的顽固性物质。将生物质转化为生物碳被认为是产生生物能源，减少温室气体排放和管理废物的可持续方式。近年来，生物炭在土壤中的改良由于其改善土壤的多种特性而受到关注。许多研究已经研究了生物炭粒径对相对松散的农业土壤的理化和水力性质的影响。但是，这种研究很少针对适合生物工程结构的压实土壤进行。当前研究的目的是研究生物炭粒径对生物工程结构压实土壤水力传导率的影响。饱和水力传导率已经研究了不同的压实土壤的K _sat），并用0.075至4.75 mm的不同粒径的生物炭进行了修正。结果表明，不同粒径的5％至15％（w / w）生物炭的修正导致粉砂的K _sat变化。当与裸露的土壤相比，有较高的ķ_坐在与粒径大于0.425毫米更大的生物炭和下ķ_坐在与尺寸比观察0.425毫米较小的颗粒。然而，在纯砂中，观察到较低的K _sat，而与生物炭的粒径无关，而最低的K _sat注意到生物炭的粒径小于150毫米。这些变化在ķ_坐在后生物炭修正归因于孔结构的改变主要是间孔土壤中，这是由生物炭的粒径控制的。本研究的发现可能对现场应用，即在生物工程结构中有用。