The confined aquifer dewatering for long-deep excavations usually encounters challenges due to complicated geotechnical conditions,large excavation sizes,and high hydraulic pressures.To propose the most efficient sche...The confined aquifer dewatering for long-deep excavations usually encounters challenges due to complicated geotechnical conditions,large excavation sizes,and high hydraulic pressures.To propose the most efficient scheme of confined aquifer dewatering for long-deep excavations,dewatering optimizations were performed using the simulation–optimization method.An open cut tunnel of the Jiangyin-Jingjiang Yangtze River Tunnel Project was taken as an example.The methods of finite element and linear programming(LP)were combined to optimize the dewatering process.A three-dimensional finite element model was developed.After simulating the pumping tests,hydraulic conductivity was inverted.Then,necessary parameters in the LP method were determined by simulating dewatering with each pumping well,and various LP models were developed based on some important influence factors such as dewatering sequence,considered pumping wells,and pumping rate limitation.Finally,the optimal pumping rates were solved and applied to the numerical model,with induced drawdown and ground settlement computed for comparison.The results indicate that the optimization can significantly reduce the required wells in the original design.Dewatering in the deepest zone exhibits the highest efficiency for long-deep excavations with gradually varying depths.For the dewatering sequence from the shallowest to the deepest zone,more pumping wells are required but less energy is consumed.Higher quantity and more advantageous locations of pumping wells in the LP model usually result in lower total pumping rate,drawdown,and ground settlement.If more pumping wells are considered in the deepest zone,pumping rate limitation of single well will only slightly increase the total pumping rate,number of required pumping wells,drawdown,and ground settlement.展开更多
We report a double Q-switched 946 nm laser with a magnesium-oxide-doped LiNbO3 （MgO：LN） electro-optic （EO） crystal and a monolayer molybdenum diselenide （MoSe2） saturable absorber （SA）. A pulsed laser diode s...We report a double Q-switched 946 nm laser with a magnesium-oxide-doped LiNbO3 （MgO：LN） electro-optic （EO） crystal and a monolayer molybdenum diselenide （MoSe2） saturable absorber （SA）. A pulsed laser diode side-pumped long neodymium-doped yttrium aluminum garnet rod （φ3×65 mm） is used as the gain medium. Large pulse energy up to 3.15 mJ and peak power up to 346 kW are generated at the repetition rate of 550 Hz, corresponding to the beam quality factors of Mx^2=3.849, My^2=3.868. Monolayer MoSe2 nanosheets applied in the experiment would be a promising SA for a passive Q-switching operation.展开更多
We report a cavity-dumped 1123 nm laser with narrow pulse width and high peak power by an Mg O: LN crystal electrooptic(EO) modulator. Based on the structural optimization design of a folded biconcave cavity using the...We report a cavity-dumped 1123 nm laser with narrow pulse width and high peak power by an Mg O: LN crystal electrooptic(EO) modulator. Based on the structural optimization design of a folded biconcave cavity using the 808 nm pulsed laser diode(LD) side-pumped ceramic Nd: YAG rod, output pulses with maximum pulse energy and peak power up to39.6 m J and 9.73 MW were obtained, corresponding to 100 Hz repetition rate and 4.07 ns pulse width. The instabilities of pulse width and pulse energy were ±1.55% and ±2.06%, respectively. At the highest repetition rate of 1 kHz, the pulse energy, pulse width, and peak power were 11.3 mJ, 5.05 ns, and 2.24 MW, respectively. The instabilities of pulse width and pulse energy were ±2.65% and ±3.47%, respectively.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41972269 and 52178384)the Project of Jiangsu Provincial Transportation Construction Bureau,China(Grant No.2021QD05).
文摘The confined aquifer dewatering for long-deep excavations usually encounters challenges due to complicated geotechnical conditions,large excavation sizes,and high hydraulic pressures.To propose the most efficient scheme of confined aquifer dewatering for long-deep excavations,dewatering optimizations were performed using the simulation–optimization method.An open cut tunnel of the Jiangyin-Jingjiang Yangtze River Tunnel Project was taken as an example.The methods of finite element and linear programming(LP)were combined to optimize the dewatering process.A three-dimensional finite element model was developed.After simulating the pumping tests,hydraulic conductivity was inverted.Then,necessary parameters in the LP method were determined by simulating dewatering with each pumping well,and various LP models were developed based on some important influence factors such as dewatering sequence,considered pumping wells,and pumping rate limitation.Finally,the optimal pumping rates were solved and applied to the numerical model,with induced drawdown and ground settlement computed for comparison.The results indicate that the optimization can significantly reduce the required wells in the original design.Dewatering in the deepest zone exhibits the highest efficiency for long-deep excavations with gradually varying depths.For the dewatering sequence from the shallowest to the deepest zone,more pumping wells are required but less energy is consumed.Higher quantity and more advantageous locations of pumping wells in the LP model usually result in lower total pumping rate,drawdown,and ground settlement.If more pumping wells are considered in the deepest zone,pumping rate limitation of single well will only slightly increase the total pumping rate,number of required pumping wells,drawdown,and ground settlement.
基金supported by the National Natural Science Foundation of China(No.61205114)the Science & Technology Coordinator Innovation Plan Project of the Shaanxi Province(No.2011KTCL01-06)the Key Laboratory Project of Shaanxi(No.2010JS112)
文摘We report a double Q-switched 946 nm laser with a magnesium-oxide-doped LiNbO3 （MgO：LN） electro-optic （EO） crystal and a monolayer molybdenum diselenide （MoSe2） saturable absorber （SA）. A pulsed laser diode side-pumped long neodymium-doped yttrium aluminum garnet rod （φ3×65 mm） is used as the gain medium. Large pulse energy up to 3.15 mJ and peak power up to 346 kW are generated at the repetition rate of 550 Hz, corresponding to the beam quality factors of Mx^2=3.849, My^2=3.868. Monolayer MoSe2 nanosheets applied in the experiment would be a promising SA for a passive Q-switching operation.
基金supported by the National Natural Science Foundation of China (No. 61205114)the Key Laboratory Project – scientific research plan of Shaanxi Provincial Department of Education (No. 2010JS112)
文摘We report a cavity-dumped 1123 nm laser with narrow pulse width and high peak power by an Mg O: LN crystal electrooptic(EO) modulator. Based on the structural optimization design of a folded biconcave cavity using the 808 nm pulsed laser diode(LD) side-pumped ceramic Nd: YAG rod, output pulses with maximum pulse energy and peak power up to39.6 m J and 9.73 MW were obtained, corresponding to 100 Hz repetition rate and 4.07 ns pulse width. The instabilities of pulse width and pulse energy were ±1.55% and ±2.06%, respectively. At the highest repetition rate of 1 kHz, the pulse energy, pulse width, and peak power were 11.3 mJ, 5.05 ns, and 2.24 MW, respectively. The instabilities of pulse width and pulse energy were ±2.65% and ±3.47%, respectively.
