| Non-explosive rock breaking methods have been gradually applied to surface or underground projects such as oil and gas mining,tunnels,rock lanes,bridges,municipalities,etc.The non-explosive rock breaking methods represented by hydraulic fracturing methods have high efficiency,less pollution,no vibration,etc.The advantages have important scientific significance and application value.However,the traditional hydraulic fracturing method may cause groundwater pollution,waste of water resources,and in particular may cause different degrees of damage to the stratum.In order to overcome the shortcomings of the existing hydraulic fracturing methods,this paper has consulted a large number of literatures,compared and analyzed the related researches of the previous hydraulic fracturing methods,and developed viscous hydrostatic rock fracture technology and equipment Related research,using a combination of theoretical analysis,laboratory research and field tests,reveals the mechanism of viscous hydrostatic pressure rock breaking,and applies the research results under hydrostatic pressure to tunnel engineering.The main research work is as follows:(1)Taking viscous fluid as the research object,the rock breaking mechanism of viscous fluid under hydrostatic pressure is systematically analyzed.Systematic theoretical analysis of viscous fluid properties,flow process in concentric annular space,rock fracture mechanics process during fracturing,and crack propagation characteristics after rock fracturing are carried out,and the criterion equations leading to the rupture of the hole wall and the crack propagation and propagation are deduced.The criterion of direction.It provides strong theoretical support for the engineering application and promotion of this technology.(2)Developed a viscous hydrostatic rock breaking system,integrated the current domestic static pressure rock breaking technology and equipment,independently developed a viscous hydrostatic rock breaking system,the system is mainly composed of fracturing device,pressure source,pipe It consists of four parts: the system and the shunt control system.The related principles of the system are simple,the operation is convenient,and it is technically and theoretically feasible.The relevant parameters of the fracturing system have been adjusted through related experiments,and more Complete fracturing equipment.(3)A viscous fluid fracturing experiment under low static pressure was carried out in a thick-walled acrylic tube.Two influencing factors of sand size and sealing material were selected for viscous hydrostatic pressure experiment,and the two sealing materials were compared and analyzed.One of them is a sealing material composed of saturated green sand with different particle sizes,and the other is a mixed sealing material composed of saturated super absorbent resin in sand.The study found that sand is mixed with saturated water absorbent resin.The pressure unloading speed of the sealing material to the viscous fluid in the fracturing device is the slowest,and the peak pressure arrival time in the sealing material is obviously lagging behind that of the sealing material of saturated green sand,and the attenuation of the stress peak is gentle,and the sealing effect is better;In addition,by changing the particle size range of the sand in the above-mentioned sealing material,it is found that the sealing effect of the sealing material mixed with standard sand and saturated superabsorbent resin is the best.(4)Based on the experimental results under low hydrostatic pressure,the viscous hydrostatic pressure rock breaking technology under high hydrostatic pressure is applied to tunnel engineering for deep hole and shallow hole test verification.The deep hole fracturing test verifies the theory of rock crack propagation under viscous hydrostatic pressure;the shallow hole fracturing test shows that the fracturing funnel produced by shallow hole fracturing has better rock-breaking depth and volume than traditional blasting funnels.Significant advantages and broad application prospects. |
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