Although a large number of tunnels and deep excavations have been constructed in Shanghai, small-strain stiffness properties natural Shanghai clay rarely reported the literature. In this study, degree inherent anisotropy was investigated triaxial apparatus equipped with local strain transducers shear-wave velocity measurement system. Three sets side-mounted bender elements, consisting one transmitter two receivers each, were installed on prismatic specimen. Two series tests specimens intact...

In 2009, a 13-story residential building founded on lightly reinforced prestressed high-strength concrete (PHC) pipe piles in Shanghai collapsed completely during the excavation of an adjacent underground garage (i.e., southern side). course construction, excavated soil had been dumped northern side and formed 10-m-high fill slope before collapse. order to identify principal cause sudden collapse, extensive field investigation was carried out immediately after accident. addition geotechnical...

This paper reports a forensic investigation on the unexpected collapse of 13-storey high-rise residential building in Shanghai soft clay. Prior to collapse, shallow excavation was carried out one side while slope filled opposite side. Despite observed breakage all piles field, preliminary numerical analysis adopting typical undrained shear strength (c u ) profile suggests that are very unlikely break. The surprising contrast has led this detailed study underlying mechanisms for through...

A numerical investigation of a propeller with swirl recovery vanes, for which experimental data exist, is performed. second vane geometry, shorter vanes to avoid the impingement tip vortices, also investigated. For baseline efficiency propulsive system increases by 2.4% respect isolated propeller. This obtained converting angular momentum in axial momentum. reduction angle near wake 48% found. Most thrust generated at root vanes. Leading-edge noise dominant source. The cause increase 20 dB...

Compared to traditional soil improvement methods such as preloading, vertical drains, or grouting injection, et al., pile-supported reinforced embankments are increasing widely employed in the construction of highways on soft soils. A series three-dimensional model tests pile-reinforced embankments, utilizing a square arrangement for pile caps, were conducted investigate effects pile-subsoil relative displacement, embankment height, tensile strength geotextiles, and clear spacing caps stress...

In order to balance the compressive stress of a silicon dioxide film and compose steady MEMS structure, silicon-rich nitride with tensile is deposited by plasma enhanced chemical vapor deposition process. Accurately measuring thermal conductivity highly desirable in design, simulate optimize devices. this paper, SiO2/SixNy bimaterial microbridge structure presented measure single steady-state measurement. The extracted as 3.25 W/(m·K). Low indicates that can still be utilized thermally...

In this paper, we will present a novel MEMS Pirani sensor with triple heat sinks. The sensors are made on SOI (Silicon On Insulator) wafers leading to very simple process and good mechanical structures as compared alternative surface micromachining processes. Moreover, the proposed has three area of loss through ambient gas is greatly enlarged one or dual sinks without increasing dimension sensor. Consequently, dynamic pressure range be enlarged.

On 27 June 2009, a 13-storey building founded on pretensioned spun high-strength concrete piles suddenly collapsed in Shanghai, China. Prior to the collapse, an underground garage was excavated south of while soil dumped its north side and formed 10 m high fill slope. A comprehensive field investigation carried out collect physical evidence relating sudden particularly damage piles. The ultimate bending moment shear capacities this type pile were determined through series full-scale tests...

In hard rock deep‐hole blasting excavation, blastholes are rarely utilized due to the clamping effect of lower rock, which affects excavation progress and restricts development application technology. Cut is a key improving speed. this paper, new cutting method designating two‐step technology was presented. The blasthole divided into upper sections without changing layout. section detonated first, creating sufficient free surface for section, secondly. This created larger cavity improved...

Abstract A model predictive control (MPC) strategy is devised to handle the issue of multi-actuators partial failure faults quadrotor vehicles. Firstly, considering a system with actuator and unknown disturbances, dynamics analyzed established. Then, MPC attitude fault-tolerant controller transform controlling angle into quadratic programming solution problem, extended state observer (ESO) evaluate perturbations, which highly greatly improves system’s suppression capability against...

A pile-supported reinforced embankment exhibits complex mechanical behavior, and the stability of is greatly influenced by soil arching. series three-dimensional model tests were conducted to investigate effects factors such as relative displacement pile-subsoil, height, tensile strength geotextiles, clear spacing pile caps on stress concentration ratio settlement. The results indicate a close relationship between arching effect piles soil. pile-soil reaches its maximum value when...

Online sellers have used several innovative strategies to find out how much customers are willing pay and encourage them different prices accordingly. Yet name your own price, what you want, opaque selling did not work as planned. Qing Li Christopher Tang suggest ways that can unlock the value of these strategies.