Abstract: The present invention discloses a crack-resistant ultra-high performance concrete (UHPC) for underground engineering in water-rich strata, preparation method, and application thereof, belonging to the technical field of building materials. The concrete is prepared from the following raw materials in parts by weight: 550-650 parts of cement, 140-180 parts of fly ash, 120-150 parts of silica fume, 200-300 parts of calcined shield tunnel slag, 30-50 parts of micron-scale magnesium oxide, 30-50 parts of nano-scale magnesium oxide, 30-50 parts of rheology-modifying material, 800-1000 parts of lightweight aggregate, 4-8 parts of water reducer, and 50-200 parts of water. The rheology-modifying material has a fluidity ratio of 106%. The present invention incorporates calcined shield tunnel slag, micron/nano-scale magnesium oxide, and lightweight aggregate into the UHPC, which effectively suppresses shrinkage and reduces crack formation.

Abstract: An oscillating shear valve of a continuous pulse generator comprises a rotator and a stator which are coaxially mounted, valve orifices are formed on the rotator and the stator, each of the valve orifices comprises a circular arc line, two straight line segments and two fillets, and is designed by establishing polar coordinate equations of the circular arc line, the straight line segments and the fillets and calculating a mud throttling area formed when the oscillating shear valve moves and determining parameters of structures of the valve orifices by a correlation coefficient index of the fluid differential pressure and a standard sinusoidal wave.

Abstract: An oscillating shear valve of a continuous pulse generator comprises a rotator and a stator which are coaxially mounted, valve orifices are formed on the rotator and the stator, each of the valve orifices comprises a circular arc line, two straight line segments and two fillets, and is designed by establishing polar coordinate equations of the circular arc line, the straight line segments and the fillets and calculating a mud throttling area formed when the oscillating shear valve moves and determining parameters of structures of the valve orifices by a correlation coefficient index of the fluid differential pressure and a standard sinusoidal wave.