An integrated strength-calculation model for earth-based construction prepared by organic clay

The earth-based construction with unique advantages of wide source of raw material and low carbon emission has attracted growing attention recently In South China, raw soils which have been used for hundreds of years are mainly organic clays with high contents of water and organic matter. This research uses reconstituted organic soil technique to prepare earth-based construction and investigate the key variables controlling compressive strength by measuring compressive strength (qu) and physical indexes including unit weight (γt), water content (wt) and specific gravity (Gst). The cementitious material used is a high-efficiency stabilizer named as CSCN, and organic clay is obtained by mixing humic acid powder (HAP) with raw clay. The presence of HAP is regarded as the consumption of CSCN, and total CSCN content (CT) can also be calculated. Firstly, a parameter taking into account the key variables is expressed as the ratio of void ratio to total CSCN content (et/CT) and the relationship of qu to et/CT is analyzed by a power function. Physical indexes of stabilized earth are dependent upon the initial physical properties and influenced by CT value, actual CSCN content, HAP content and curing time. And then, the calculation formulae for physical indexes are obtained by the multiple linear regression and power regression analysis by defining dimensionless ratios of the after-curing physical indexes to the initial ones. Ultimately, a strength-calculation model with a deviation between calculated strength and experimental results less than 10% is established based on et/CT. The model is proved to be very useful for the design and preparation of earth-based construction with organic matter.