Experimental Investigation into Multistage versus Conventional Triaxial Compression Tests for a c-phi Soil

The procedure for conventional triaxial compression (CTC) test requires three separate soil specimens to be examined to failure under different confining pressures so that Mohr-Coulomb (or stress path) failure envelope can be determined and soil shear strength parameters can be obtained. An alternative procedure is the multi-stage triaxial (MST) compression test, which requires only one soil specimen to be tested at three stages of shearing with different confining pressures. There are several advantages for using MST over CTC, which apart from fewer soil specimens, include less laboratory time consumption and reduced effects of heterogeneity among the specimens tested. However, it has been argued in the literature that the advantages of using MST may be compromised by its inability to obtain reliable soil behavior or accurate shear strength parameters. In this paper, the accuracy of MST compared to CTC is investigated for a c-phi soil, and a simple procedure that can be adopted to rectify the MST results is proposed

Urban water mass balance analysis

Planning for “water-sensitive” cities has become a priority for sustainable urban development in Australia. There has been little quantification of the term, however. Furthermore, the water balance of most cities is not well known. Following prolonged drought, there has also been a growing need to make Australian cities more water self-reliant: to source water from within. This article formalizes a systematic mass-balance framework to quantify all anthropogenic and natural flows into and out of the urban environment. Quantitative performance indicators are derived, including (1) degree of system centralization; (2) overall balance; potential of (3) rainfall, (4) stormwater, and (5) wastewater to offset current demand; and (6) water cycle rate. Using the method, we evaluate Sydney, Melbourne, South East Queensland and Perth using reported and modeled data. The approach makes visible large flows of water that have previously been unaccounted and ignored. It also highlights significant intercity variation. In 2004–2005, the cities varied 54% to 100% in their supply centralization, 257% to 397% in the ratio of rainfall and water use, 47% to 104% in their potential stormwater recycling potential, and 26% to 86% in wastewater recycling potential. The approach provides a practical, water-focused application of the urban metabolism framework. It demonstrates how the principles of mass balance can help foster robust water accounting, monitoring, and management. More important, it contributes to the design and quantitative assessment of water-sensitive cities of the future