Study on the Failure Surface of Heterogeneous Soil at the Passive State
Study on the Failure Surface of Heterogeneous Soil at the Passive State Fei Song*, Rui-Zhi Cheng, Li-Qiu Ma, Xi-Bin Tang, Wen-Zhong Yuan Institute of Geotechnical Engineering, School of Highway Engineering, Chang’An University, Xi’an, 710064, P.R. China Guizhou Electricity Engineering Construction Supervise Company, Guiyang, 550005, P.R. China Guizhou Electric Power Design Institute and Research Institute, Guiyang, 550002, P.R. China songf1980@163.com
Evaluation of active earth pressure by the generalized method of slices
The generalized method of slices, commonly used in slope stability analysis, can be extended to determine active earth pressures applied to various types of supports. The governing force and moment equlibrium equations are given. In a similar manner to slope stability analysis, the methods of optimization are used to define the critical slip surface that is associated with the maximum wall pressure. Examples show that the approaches give active earth pressures identical to the Rankine solution for gravity walls. For other types of support, such as anchored or strutted walls, the earth pressure is determined by assigning appropriate locations of the point of application on the wall. It has been found that applying the restrictions of physical admissibility is more vital in earth pressure problems than in slope stability assessments.Key words: earth pressure, limit equilibrium method, the method of slices, retaining walls.
Fully Integrated Bidirectional CMOS-MEMS Flow Sensor With Low Power Pulse Operation
Leveraging More-than-Moore technology, we demonstrate an integrated CMOS MEMS flow sensor via a very compact system on chip (SoC) that can sense the bidirectional N2 gas flow. Our SoC features a very low-noise instrumentation amplifier that is implemented on a CMOS wafer and serves as a readout integrated circuit for a thermoresistive micro-calorimetric flow sensor which is fabricated on a MEMS wafer. A compact heterogeneous integration is achieved by combining the two wafers via the proprietary InvenSense AlN process. The measured sensitivity of our CMOS MEMS flow sensor is 98 mV/sccm which is three times better than the state-of-the-art counterpart. The flow range measured by our SoC is from −26 to 26 m/s (from −50 to 50 sccm). Moreover, the pulsed heater operation makes this proposed SoC flow sensor a very low power (<9 mW) and, thus, a promising candidate for the Internet-of-Things applications in smart home/green buildings.