Informatics Publishing Limited

Feng Xu ¹, Chunhe Yang ¹, Yintong Guo ¹, Tongtao Wang ¹, Lei Wang ¹, Ping Zhang ²

Affiliations
1 State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, Hubei, CN
2 State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, CN

Abstract

To understand the effect of confining pressure on the mechanical properties of thermally treated coarse sandstone, uniaxial and triaxial compression tests were conducted for six groups of thermally treated sandstone from Xujiahe Formation in southwestern China under confining pressures of 0-40 MPa. The test results indicate that 600°C is a critical threshold of the thermal damage of sandstone by SEM and mechanical tests. When temperature is below 600°C, few micro cracks are observed by SEM. Peak strength, elastic modulus, cohesion and internal friction angle remain constant or increase with increasing temperature and all these values decrease when temperature is above or equal to 600°C under different confining pressures. Under the uniaxial and low confining pressure (≤ 5 MPa), the failure mode shows single or multiple splitting planes and it is easier to generate complex cracks with increasing temperature. Under high confining pressure (10-40 MPa), the failure mode shows a simple shear plane after treatment at different temperatures, i.e. 25-1000°C. The results may provide guidance for rock engineering design after high temperature exposure.

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Jihao Zhou ¹, Jie Liu ¹, Zhiwei Zhao ¹, Ping Zhang ², Jie Shi ³

Affiliations
1 Department of Military Facilities, Army Logistics University of PLA, Chongqing, 401331, CN
2 Bureau of Navy Engineering Design and Research, Beijing, 100070, CN
3 Air Force Unit 93413, Yongji, 044500, CN

Abstract

Solid waste management is an inevitable challenge for Chinese government during the island construction practice in the South China Sea. Composting, if it is properly put into application, can constitute an environment friendly and sustainable method for solid waste management on these newly-built artificial coral reefs, due to its great potential to improve coral sand soil with low cost. As the key components of island solid wastes, kitchen waste, faeces and sewage sludge were combined in ratio of 1:1:1, which conformed to the actual production and constituted a mixed waste system. Thus, using a self-made intelligent reactor, this paper presented the performance and potential of mixed treatment of kitchen waste, faeces and sewage sludge through co-composting with the coamendment of sawdust and cornstalk. A series of process parameters were monitored, the laws about degradation and resynthesis of organic matter, transformation and loss of nitrogen were revealed in this paper. The results indicated that applying the aerobic composting technology to the solid waste treatment in the mixed system of kitchen waste, faeces and sewage sludge with coamendment of sawdust and cornstalk was feasible, and the optimal mixed ratio of total waste to coamendment was 4:1 on analysis of technique and economics.

Keywords

Wastes In The Islands, Kitchen Waste, Faeces, Co-Composting, Process Dynamics.

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