A frozen rock dam foundation blasting excavation device and method based on a multi-layer transmission-reflection energy concentrating structure

Abstract

The application provides a frozen rock dam foundation blasting excavation device and method based on a multi-layer transparent and reflective energy concentration structure, which comprises a blast hole, a flexible cushion layer, a multi-layer energy dissipation ball, explosives and a blocking material. The blast hole is drilled on the control base surface of the frozen rock dam foundation. The flexible cushion layer is laid at the bottom of the blast hole. The multi-layer energy dissipation ball is tightly pressed on the flexible cushion layer and is composed of materials with high and low wave impedance alternately changing from outside to inside. The explosives are arranged above the multi-layer energy dissipation ball. The blocking material is arranged above the explosives and is used for blocking and landfill. Under the action of the explosion stress wave, the application can reflect more explosion energy to the blast hole wall, enhance the blasting effect, realize the energy concentration blasting above the bottom side of the blast hole, significantly reduce the transmission energy to the bottom below the blast hole, reduce the damage of the remaining rock mass and realize the energy dissipation effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rock mass blasting, and particularly relates to a frozen rock dam foundation blasting excavation device and method based on a multi-layer transmission-reflection energy concentration structure, which is suitable for hard rock foundation blasting excavation in the fields of water conservancy and hydropower, transportation, civil construction and the like. BACKGROUND

[0002] The dam foundation excavation quality is crucial in water conservancy and hydropower engineering. In the process of rock mass blasting excavation, due to the action of explosive load, the rock is broken by blasting, and at the same time, the retained rock mass is inevitably damaged by dynamic force. The construction quality is closely related to the excavation quality of the rock foundation surface. In particular, for the frozen rock dam foundation, the rock mass strength is enhanced compared with the conventional rock mass, and the blasting explosive consumption is significantly increased, which will intensify the damage to the bottom retained rock mass. At the same time, for the frozen rock near the blast hole, the ice microcracks in the rock will rapidly gasify under the condition of high temperature and blast heat, the development of the surrounding rock microcracks will increase, and the blast gas will more easily penetrate into the rock mass, thus playing a role of expanding and cracking the rock, which will further intensify the damage to the retained rock mass at the bottom of the hole. Therefore, it is urgent to improve the conventional blasting to efficiently complete the excavation of the rock foundation while ensuring the quality.

[0003] The related art arranges a high wave impedance pad at the bottom of the blast hole to reflect the blast shock wave, enhance the breaking effect of the upper rock mass, and reduce the damage of the shock wave to the retained rock mass in the hole bottom direction. However, the single-layer high wave impedance pad has limited transmission and reflection effects on the stress wave, and at the same time, the bottom of the conical pad is prone to tilt during arrangement. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a frozen rock dam foundation blasting excavation device and method based on a multi-layer transmission-reflection energy concentration structure, which can enhance the energy concentration effect on the hole wall at the hole bottom while ensuring the energy dissipation of the hole bottom based on the energy dissipation structure in the vertical blast hole.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] A frozen rock dam foundation blasting excavation device based on a multi-layer transmission-reflection energy concentration structure, comprising:

[0007] a blast hole drilled on the control surface of the frozen rock dam foundation;

[0008] a flexible pad layer laid at the bottom of the blast hole;

[0009] a multi-layer energy dissipation ball tightly pressed on the flexible pad layer, which is composed of materials with high and low wave impedance alternately changing from outside to inside;

[0010] explosive arranged above the multi-layer energy dissipation ball;

[0011] The blocking material is arranged above the explosive and is used for blocking the landfill.

[0012] Further, the material of the flexible cushion layer is a mixture of one or more of fine sand, rock powder and loose sand.

[0013] Further, the thickness of the flexible cushion layer is 6-10 cm.

[0014] Further, the outer diameter of the multi-layered energy-dissipating ball is 4-6 mm smaller than the inner diameter of the blast hole.

[0015] Further, the multi-layered energy-dissipating ball is made of metal, and different metals are selected to achieve different material properties.

[0016] Further, the calculation method of the wave impedance of the material is as follows:

[0017]

[0018]

[0019] In the formula, E is the elastic modulus of the material, ρ is the density of the material, μ is the Poisson's ratio of the material, V p is the longitudinal wave velocity of the material, and ρV p is the wave impedance of the material.

[0020] Further, the multi-layered energy-dissipating ball is made of n layers of materials and has an outer diameter d1, the innermost layer of material is in the form of a sphere and has an outer diameter d2, the outer diameter of the innermost layer of material is 1 / 2-2 / 3 of the outer diameter of the multi-layered energy-dissipating ball, the remaining layers are in the form of spherical shells and have uniform thickness, and the thickness of the remaining layers is

[0021] Further, by increasing the number of layers of the material of the multi-layered energy-dissipating ball and reducing the thickness of each layer of material, the energy-dissipating and vibration-reducing effects of the blast hole bottom and the energy-dissipating and crushing effects between blast holes can be improved.

[0022] Further, an interface is formed between adjacent layers of material, and the reflection wave intensity and the transmission wave intensity of the interface are represented by the following formulas, respectively:

[0023]

[0024]

[0025] In the formula, I is the incident stress wave intensity, R is the reflection wave intensity, T is the transmission wave intensity, ρ a is the density of the material in front of the interface, ρ b is the density of the material behind the interface, (V p ) a is the longitudinal wave velocity of the material in front of the interface, and (V p) b Let ρ be the longitudinal wave velocity of the medium material behind the interface. a (V p ) a Let ρ be the wave impedance of the dielectric material in front of the interface. b (V p ) b The impedance of the dielectric material behind the interface.

[0026] A method for blasting excavation of frozen rock dam foundation based on a multi-layered transmissive and reflective energy-conducting structure includes the following steps:

[0027] Drill blast holes on the control surface of the frozen rock dam foundation;

[0028] A flexible padding layer is laid at the bottom of the borehole;

[0029] A multi-layered energy-dissipating ball is placed at the bottom of the borehole and pressed tightly onto a flexible pad. The multi-layered energy-dissipating ball is composed of multiple layers of materials with alternating high and low wave impedance arranged from the outside to the inside.

[0030] After loading explosives onto the multi-layered energy-dissipating spheres inside the borehole, the hole is plugged and filled.

[0031] Initiate the detonation.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] 1. This invention enables more explosive energy to be reflected onto the borehole wall under the action of explosive stress wave, thereby enhancing the blasting effect and achieving focused blasting above and below the bottom of the borehole. At the same time, it significantly reduces the energy transmitted to the bottom of the borehole, reduces damage to the remaining rock mass, and achieves an energy dissipation effect.

[0034] 2. This invention enhances the blasting effect, strengthens the post-blast root barrier elimination function, eliminates the need for subsequent processing, reduces labor and charge loss, effectively improves blasting charge efficiency, and saves engineering costs.

[0035] 3. It reduces damage to frozen rock masses and improves the quality of engineering construction.

[0036] 4. The invention has low cost and is easy to operate. The materials involved in the invention structure are all readily available and inexpensive. Attached Figure Description

[0037] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are intended to explain the invention, but do not constitute an undue limitation thereof. In the drawings:

[0038] Figure 1 This is a schematic diagram of the blasting excavation device for frozen rock dam foundation based on a multi-layer transmissive and reflective energy-concentrating structure according to the present invention.

[0039] Figure 2 Schematic diagram of the energy dissipation principle of the present application.

[0040] Figure 3 Schematic diagram of the frozen rock dam foundation blasting excavation method based on the multi-layer transparent and reflective energy concentration structure of the present application.

[0041] In the figure: 1, blocking material; 2, explosive; 3, multi-layer energy dissipation ball; 4, flexible cushion layer; 5, rock mass; 6, control base surface; 7, blast hole. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

[0043] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms “center”, “longitudinal”, “transverse”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms “first”, “second” and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by “first”, “second” and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of “a plurality of” is two or more.

[0044] In the related art, a single layer of high wave impedance cushion block is arranged at the bottom of the blast hole 7 to reflect the explosion shock wave, enhance the breaking effect of the upper rock mass, and at the same time reduce the damage of the shock wave in the direction of the bottom of the blast hole to the reserved rock mass, but the single layer of high wave impedance cushion block has limited stress wave transmission and reflection ability, the present application provides a frozen rock dam foundation blasting excavation device based on a multi-layer transparent and reflective energy concentration structure, which can reflect and transmit stress waves multiple times, reflect more explosion energy on the blast hole wall, enhance the blasting effect, realize energy concentration blasting above the bottom of the blast hole, and at the same time significantly reduce the transmission energy to the bottom of the blast hole, reduce the damage to the reserved rock mass, and realize the energy dissipation effect.

[0045] First embodiment

[0046] The present application provides a frozen rock dam foundation blasting excavation device based on a multi-layer transparent and reflective energy concentration structure, comprising:

[0047] The blast hole 7 is drilled on the control base surface 6 of the frozen rock dam foundation;

[0048] a flexible pad 4 arranged at the bottom of the blast hole;

[0049] a multilayered energy dissipation ball 3 tightly pressed on the flexible pad 4 and composed of materials with alternating high and low wave impedance from outside to inside;

[0050] an explosive 2 arranged above the multilayered energy dissipation ball 3;

[0051] a plugging material 1 arranged above the explosive 2 for plugging and filling.

[0052] As shown in FIG. 1, it is a schematic diagram of the device for blasting excavation of frozen rock dam foundation based on the multilayered transparent and reflective energy concentration structure according to the present application. Figure 1 As shown in FIG. 2, it is a schematic diagram of the energy dissipation principle according to the present application. Figure 2

[0053] The device for blasting excavation of frozen rock dam foundation based on the multilayered transparent and reflective energy concentration structure according to the present application has the working process as follows:

[0054] After initiation, the air shock wave first transmits and reflects at the interface between the multilayered energy dissipation ball 3 at the bottom of the blast hole 7 and the air. For the multilayered energy dissipation ball 3, the wave impedance alternates from outside to inside (high, low, high, low, …), and according to the propagation law of stress wave at the interface between different media, it can be found that a considerable proportion of energy is reflected to the peripheral hole wall of the blast hole 7 in the form of stress wave, thereby enhancing the rock breaking effect of the hole wall, and the stress wave transmitted into the multilayered energy dissipation ball 3 will reflect and transmit again at the interface between two layers of materials, the reflected wave will also reflect and transmit at the outer layer of material, and a part of the transmitted explosive energy will act on the peripheral hole wall of the blast hole 7 again, thereby enhancing the rock breaking effect of the hole wall. Such a cycle continues until the stress wave is transmitted to the bottom of the blast hole 7, and in this process, a large amount of explosive energy is reflected to the peripheral hole wall of the blast hole 7, thereby enhancing the rock breaking effect of the hole wall, realizing the energy concentration effect, and at the same time greatly reducing the energy transmitted to the bottom of the blast hole 7, and reducing the damage to the retained rock mass 5.

[0055] The device for blasting excavation of frozen rock dam foundation based on the multilayered transparent and reflective energy concentration structure according to the present application has the energy concentration device arranged at the bottom of the blast hole 7, which has the functions of reflecting the blast wave and increasing the blasting effect on the peripheral hole wall of the blast hole 7. The energy concentration device realizes the energy concentration between holes, enhances the breaking effect, and reduces the damage to the retained rock mass 5 according to the propagation law of blast wave in media. When dealing with frozen rock with higher strength, the use of this blasting design method can effectively reduce the explosive consumption and reduce the damage to the retained rock mass 5.

[0056] In the embodiment of the present application, the flexible pad 4 is arranged between the multilayered energy dissipation ball 3 and the bottom of the blast hole 7.

[0057] ​The flexible cushion 4 has a thickness of 6-10 cm, and the material of the flexible cushion 4 is a mixture of one or more of fine sand, rock powder and pine sand.

[0058] By arranging the flexible cushion 4, the damage of the shock wave propagating towards the bottom of the blast hole 7 to the reserved rock mass 5 is further reduced.

[0059] In the embodiment of the present application, the blocking material 1 is usually mud.

[0060] In the embodiment of the present application, the multilayered disaggregation energy ball 3 is made of metal, and different metals are selected to realize different material properties. The material properties mainly include density, elastic modulus and Poisson's ratio. According to the material properties, the wave impedance of the material can be obtained, and the material property difference of the adjacent layers is determined.

[0061] The calculation method of the wave impedance of the material is as follows:

[0062]

[0063] In the formula, E is the elastic modulus of the material, p is the density of the material, μ is the Poisson's ratio of the material, V p is the longitudinal wave velocity of the material, and pV p is the wave impedance of the material.

[0064] In the embodiment of the present application, the outer diameter of the multilayered disaggregation energy ball 3 is 4-6 mm smaller than the inner diameter of the blast hole 7. In order to make the multilayered disaggregation energy ball 3 smoothly put into the bottom of the blast hole 7, the multilayered disaggregation energy ball 3 and the blast hole 7 wall leave a gap of 4-6 mm, and the multilayered disaggregation energy ball 3 structure is not completely broken under the impact of the explosion, so that the multilayered disaggregation energy ball 3 at the bottom of the blast hole 7 loses the role of reflecting stress waves. Therefore, the multilayered disaggregation energy ball 3 should have a certain structural strength. Therefore, the high wave impedance layer selects cast iron with high strength, which is low in cost and can achieve good reflection effect. The low wave impedance layer can use an alloy of cast iron and light metal to change the wave impedance of the material. For example, the light metal can be selected as aluminum.

[0065] Suppose that the multilayered disaggregation energy ball 3 is made of n layers of materials and has an outer diameter of d1, the innermost layer of material is a spherical structure and has an outer diameter of d2, the outer diameter of the innermost layer of material is 1 / 2-2 / 3 of the outer diameter of the multilayered disaggregation energy ball 3, and the remaining layers of material are spherical shell structures with consistent thicknesses, and the thicknesses of the remaining layers are which is usually 5-10 mm.

[0066] When the structures of different layers are required to be cast, in order to achieve specific requirements of material properties, some alloy elements are added in the metal smelting process or subsequent heat treatment processes are increased, and the specific smelting and casting methods are selected according to actual conditions.

[0067] In the embodiment of the present application, by increasing the number of layers of the multi-layered disaggregation energy ball 3 material and reducing the thickness of each layer of material, the blasting effect is enhanced and the damage to the remaining rock mass 5 is reduced. That is, the more layers of the multi-layered disaggregation energy ball 3 material, the stronger the blasting effect and the less damage to the remaining rock mass 5.

[0068] In the embodiment of the present application, the center of the multi-layered disaggregation energy ball 3 is flush with the control base surface 6 of the frozen rock dam, and the upper hemisphere plays a role of reflecting stress waves. When flush, the reflected energy can act on the rock mass to be blasted. When too low, the reflected energy can cause damage to the remaining rock mass below the dam base surface. When too high, the reflected energy reduces the effect of excavating the dam base surface, causing root canes to remain.

[0069] In the embodiment of the present application, the blast product forms a blast gas wave impedance of ρV p气 = 3.6 x 10 6 kg·m -3 ·m·s -1 Therefore, considering the properties of the multi-layered disaggregation energy ball 3 material, high wave impedance cast iron can be selected to make the high wave impedance layer have a wave impedance of ρV p高 = 4.16 x 10 7 kg·m -3 ·m·s -1 , cast iron with other metals is selected as the low wave impedance layer, which has a wave impedance of ρV p低 = 2.25 x 10 7 kg·m -3 ·m·s -1 , and the sand and gravel in the flexible pad layer 4 between the multi-layered disaggregation energy ball 3 and the bottom of the blast hole 7 has a wave impedance of ρV p沙 = 4.25 x 10 6 kg·m -3 ·m·s -1 .

[0070] An interface is formed between adjacent layers of material, and the reflected wave intensity and transmitted wave intensity of the interface are represented by the following formulas, respectively:

[0071]

[0072]

[0073] In the formulas, I is the incident stress wave intensity, R is the reflected wave intensity, T is the transmitted wave intensity, ρ a is the density of the material in front of the interface, ρ b is the density of the material behind the interface, (V p ) a is the longitudinal wave velocity of the material in front of the interface, (V p ) b is the longitudinal wave velocity of the material behind the interface, ρa (V p ) a Z0 is wave impedance of interface front medium material, p b (V p ) b Z1 is wave impedance of interface rear medium material.

[0074] In one embodiment of the present application, the transmission and reflection intensity of the hole bottom disperse energy ball of different layer structure is counted:

[0075]

[0076] For the multilayer disperse energy ball 3 of 5 layer structure (high, low, high, low, high wave impedance), the intensity of the explosion generated air shock wave is defined as I, then the intensity of the wave finally reflected from the front is 0.72I, and the intensity of the wave transmitted from the rear to the sand and gravel is 0.40I.

[0077] When the energy gathering device is a uniform material, and the material is a high wave impedance material, the intensity of the wave finally reflected from the front is 0.60I, and the intensity of the wave transmitted from the rear to the sand and gravel is 0.57I.

[0078] Therefore, it can be found from the derivation process that the reflection energy gathering effect is enhanced with the increase of the number of layers of the wave impedance alternately changing from outside to inside (high, low, high, low, …), and the disturbance to the retained rock mass 5 is smaller.

[0079] In one specific embodiment of the present application, taking the blasting excavation of the frozen rock dam foundation protection layer of a certain water conservancy and hydropower project as an example, in the actual project, it is necessary to reduce the damage of the dam foundation blasting and obtain good flatness. Step blasting is adopted, the vertical blast hole 7 is drilled, the drilling diameter is Φhole=90mm, the rock foundation surface is horizontal, the drilling depth is 4.27m, the plugging length is 2.17m, the interval row distance is 2.5m×2.0m, and the hole bottom initiation mode is adopted.

[0080] The specific implementation process of the frozen rock dam foundation blasting excavation device based on the multilayer transmission and reflection energy gathering structure of the present application is as follows:

[0081] The multilayer disperse energy ball 3 is prefabricated, the disperse energy structure is prefabricated according to the diameter of the blast hole 7, the structure shape is as shown in Figure 2 , n=3, and the size requirements are:

[0082] From inside to outside, Φ1=50mm, Φ2=70mm, and Φ3=87mm.

[0083] In a steel mill, according to the casting process of cast iron and related materials, different ingredients and contents of related raw materials are added to obtain two different wave impedance materials, which are divided into high wave impedance layer: p p高 =4.16×107 kg·m -3 ·m·s -1 , low wave impedance layer: pV p低 =2.25×10 7 kg·m -3 ·m·s -1 , so that the wave impedance of the 3-layer composite structure is divided from outside to inside into a high wave impedance layer, a low wave impedance layer and a high wave impedance layer, so that a multi-layer reflection structure with different reflectivity and transmissivity can be realized, and the bottom energy dissipation blasting of the blast hole 7 can be realized.

[0084] According to the design requirements, the drilling design is carried out, the flexible cushion 4 of the sandstone type is strictly laid according to the requirements, the thickness of the flexible cushion 4 is controlled, and then the multi-layer reflection hole bottom energy dissipation spherical structure is placed, the multi-layer reflection spherical hole bottom energy dissipation structure is placed into the blast hole 7 from the hole, and the multi-layer reflection spherical hole bottom energy dissipation structure is placed into the blast hole 7 from the hole.

[0085] After the multi-layer reflection hole bottom energy dissipation structure is placed, the charge is continued to be placed into the blast hole 7 in the form of a Φ56mm diameter cartridge, until the charging is completed, then the blast hole 7 is blocked with silt, and the blocking depth is 2.17m.

[0086] Blasting effect detection: according to the expected requirements, the blasting is carried out, after the blasting is completed, the contour surface of the retained rock mass 5 of the dam foundation after excavation is detected, it can be seen that the multi-layer reflection spherical hole bottom energy dissipation blasting design method has more intense blasting effect in the upper to-be-blasted rock mass, the to-be-blasted rock mass in the blasting area has higher fragmentation degree, the post-blasting flatness is higher, the root can is less, the inter-hole energy concentration blasting effect is realized, and at the same time, the damage depth of the retained rock mass 5 can be measured by using sound wave detection, the detection result shows that the damage degree of the retained rock mass 5 is reduced, the damage reduction effect of the retained rock mass 5 is realized, and the hole bottom energy dissipation blasting effect is realized.

[0087] Second embodiment

[0088] The application also provides a frozen rock dam foundation blasting excavation method based on a multi-layer transmission and reflection energy concentration structure, as shown in the figure, comprising the following steps: Figure 3

[0089] Drilling a blast hole 7 on the control surface of the frozen rock dam foundation;

[0090] Laying a flexible cushion 4 at the bottom of the blast hole 7;

[0091] Placing a multi-layer energy dissipation ball 3 into the bottom of the blast hole 7 and tightly pressing it on the flexible cushion 4, the multi-layer energy dissipation ball 3 is composed of a plurality of layers of wave impedance high-low alternating change materials arranged from outside to inside;

[0092] After loading explosive 2 on the multi-layer energy dissipation ball 3 in the blast hole 7, blocking and filling are carried out; ​

[0093] The initiation is performed.

[0094] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A frozen rock dam foundation blasting excavation device based on a multi-layer transmissive and reflective energy concentrating structure, characterized in that, It comprises: a blast hole drilled on the control base surface of the frozen rock dam foundation; a flexible cushion layer laid on the bottom of the blast hole; a multilayer energy dissipation ball tightly pressed on the flexible cushion layer, which is composed of materials with high and low wave impedance alternately changing from outside to inside; explosive arranged above the multilayer energy dissipation ball; stuffing arranged above the explosive for plugging and filling; The outer diameter of the multilayer energy dissipation ball is 4 to 6 mm smaller than the inner diameter of the blast hole; The multilayer energy dissipation ball is made of metal, and different metals are selected to achieve different material properties; The multi-layered energy dissipation ball is made of layer materials and has an outer diameter of , the material of the innermost layer is in a spherical structure and has an outer diameter of , the outer diameter of the material of the innermost layer is 1 / 2-2 / 3 of the outer diameter of the multi-layered energy dissipation ball, the remaining layers are in a spherical shell structure and have a uniform thickness, and the thickness of the remaining layers is ; By increasing the number of layers of the multilayer energy dissipation ball material and reducing the thickness of each layer of material, the energy concentration and crushing effect between blast holes and the energy dissipation and vibration reduction effect at the bottom of the blast hole can be improved.

2. The frozen rock dam foundation blasting excavation device based on the multilayer transparent and reflective energy concentration structure according to claim 1, characterized in that: The material of the flexible cushion layer is a mixture of one or more of fine sand, rock powder and loose sand.

3. The frozen rock dam foundation blasting excavation device based on the multilayer transparent and reflective energy concentration structure according to claim 1, characterized in that: The thickness of the flexible cushion layer is 6-10 cm.

4. The device according to claim 1, characterized in that, The calculation method of the wave impedance of the material is: Equation (1) Formula (2) wherein is the material elastic modulus, is the material density, is the material Poisson's ratio, is the material longitudinal wave speed, is the material wave impedance.

5. The frozen rock dam foundation blasting excavation device based on the multilayer transparent and reflective energy concentration structure according to claim 1, characterized in that: An interface is formed between adjacent layers of materials, and the reflected wave intensity and transmitted wave intensity of the interface are represented by the following formulas, respectively: Formula (3) Equation (4) wherein is the incident stress wave intensity, is the reflected wave intensity, is the transmitted wave intensity, is the density of the material in front of the interface, is the density of the material behind the interface, is the longitudinal wave velocity of the material in front of the interface, is the longitudinal wave velocity of the material behind the interface, is the wave impedance of the material in front of the interface, is the wave impedance of the material behind the interface.

6. A method for blasting excavation of rock dam foundation based on multi-layered trans-reflective energy concentrating structure, characterized in that, The frozen rock dam foundation blasting excavation device based on the multilayer transparent and reflective energy concentration structure according to any one of claims 1 to 5 comprises the following steps: Drilling a blast hole on the control base surface of the frozen rock dam foundation; Laying a flexible cushion layer on the bottom of the blast hole; Placing a multilayer energy dissipation ball into the blast hole and tightly pressing it on the flexible cushion layer, the multilayer energy dissipation ball is composed of materials with high and low wave impedance alternately changing from outside to inside; After loading explosive above the multilayer energy dissipation ball in the blast hole, plugging and filling is carried out; Initiating the explosion.

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