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Tianluoshan site (5000∼2500 BC), which belongs to the Hemudu culture, has suffered damages from the hydraulic effect like other Chinese earthen sites in moist circumstance. Tung oil and sticky rice juice, as Chinese traditional building materials, were chosen as the additives in this study. Tung oil has the property of good waterproofness, fast dry-up, and quick film-forming by oxidation. Sticky rice juice has the advantage of high glutinousness, good tenacity, and low expandability. The study is to figure out the best performing mixture of tung oil and sticky rice juice to decrease the permeability of soil and increase its strength to facilitate excavations at archeological sites enlarging the display of layers of cultures. Meanwhile, the color of the site soil after reinforcement must be maintained for a long time. From the direct shear tests and the falling head test of 9 specimens mixed in different mass ratios, it was confirmed that the optimal mass ratio of the tung oil, the sticky rice juice, and the soil was 5 : 10 : 85. The treated soil specimen of the optimal mass ratio had the largest increment of shearing strength. The self-standing height of the vertical soil wall increases correspondingly from 2.63 m to 6.18 m, which could enlarge the step height when excavating a deep earthen site and extend the display height at the protection stage. The treated soil at the optimal mass ratio also showed the largest decrement of permeability coefficient from 1.257 × 10−5 cm/s of the untreated soil to 1.627 × 10−6 cm/s, which could reduce the hydraulic effect to the soil. The microstructures of the 9 specimens in different mass ratios were observed by SEM. The results showed that the glutinousness of sticky rice juice could cohere soil particles together, and the tung oil could then form oxidation film wrapping around the particle groups. In order to meet the aesthetic requirements of earthen sites conservation, the surface color contrast tests were used to measure the color change induced by the two additives. The surface contrast tests showed that the treated soil at the optimal mass ratio had the minimum variation of the surface, which could satisfy the basic requirements of earthen sites protection. [ABSTRACT FROM AUTHOR]

Two digital image methods based on scanning electron microscope (SEM) and computed tomography (CT) were proposed to study the microstructural characteristics of staple fibers and continuous filament geotextiles. Two-dimensional (2D) image analysis was developed for SEM images using a machine-learning-based segmentation algorithm. Three-dimensional (3D) image analysis of the CT images was based on 3D reconstruction and a pore network model. The fiber orientation distribution, porosity, pore size distribution (PSD), and characteristic pore size O 95 determined from image analysis were compared with the theoretical equation and bubble point test (BBP) results. It is shown that 2D and 3D image analyses can accurately measure the fiber orientation distribution of the geotextiles. The porosity values obtained using 3D imaging were comparable to theoretical values. The PSD curves obtained in the BBP tests were in good agreement with those obtained using the 3D image method. O 95 sizes of continuous filament geotextiles estimated by 2D image analysis compared well with O 95 sizes obtained by BBP tests, whereas this was not the case for staple fiber geotextiles. The O 95 pore throat sizes of the two nonwoven geotextiles determined by 3D image analysis were comparable to the BBP test-based values and 2D image analysis-based values. • The applicability and results of 2D and 3D image methods for measuring the microstructure characteristics of nonwoven geotextiles were discussed. • A machine learning-based 2D image method without complex sample preparation and parameter tuning was proposed. • 2D image analysis have accurate results of O 95 sizes for continuous filament nonwoven geotextiles. • 3D image analysis is a good approach for determining the pore characteristic of nonwoven geotextiles. [ABSTRACT FROM AUTHOR]