Step grading explosive filling method for roadway tunneling

Abstract

The invention discloses a stepped graded explosive filling method for roadway tunneling, which comprises the following steps: before blasting construction, according to the material parameter difference and the detonation velocity difference of adjacent charging sections in a stepped charging structure, measuring the reflection intensity and the energy transfer sequence of blast waves in blast holes one by one, and establishing an energy propagation trajectory diagram of each blast hole; and a boundary reflection response spectrogram is generated at the final position of the energy propagation trajectory. By constructing an energy propagation track and a coupling parameter scale chain and accurately regulating and controlling a charging structure and an energy release process, layered energy transfer and time sequence avoidance are realized, energy turn-back and advanced detonation are eliminated, vibration and overexcavation risks are remarkably reduced, the blasting efficiency, safety and construction controllability are improved, and a stable and adjustable energy balance closed loop is formed. According to the method, the tunneling crushing efficiency, the construction controllability and the field safety margin can be improved at the same time, and a quantifiable feedback basis is provided for closed-loop monitoring correction and engineering popularization.

Description

Technical Field

[0001] This invention belongs to the field of blasting construction technology, specifically relating to a step-by-step method for loading explosives for tunnel excavation. Background Technology

[0002] Stepped-type explosive loading is a blasting method used in underground mining or tunnel construction. Its core idea is to fill different types or quantities of explosives at different depths within the blast hole, creating a stepped charge structure. This structure allows for the spatial layering of explosive energy, enabling better control of the energy propagation path and fragmentation effect during blasting. This improves rock breaking efficiency while effectively avoiding over-excavation, under-excavation, and disturbance of the surrounding rock. By optimizing the charge structure and loading method, directional fracturing and smooth collapse of the tunnel face are achieved, reducing construction vibration and flyrock risks, and improving construction safety and work quality. It is a refined blasting technology that combines energy utilization efficiency with construction controllability.

[0003] In existing technologies, tunnel excavation often employs multi-stage charging or continuous loading blasting methods. However, due to differences in detonation velocities between different charge stages, and inconsistencies in the type, density, and acoustic impedance of the borehole wall medium, wave impedance reflection effects are easily formed at the boundaries of stepped charge stages. This effect causes partial reflection and superposition of blast stress waves in the boundary region, resulting in energy being trapped in the middle section, forming a local energy return trap. Explosion waves trapped in the energy return trap will oscillate back and forth multiple times in a short period, causing premature loosening of the middle section rock mass before it enters the detonation sequence, and even inducing the self-excitation of unexploded ordnance, resulting in blasting process disorder. Such energy return phenomena not only disrupt the original tunneling sequence control rules but may also trigger abrupt changes in the stress field at the tunnel face, leading to over-breaking of the surrounding rock, collapse, or chain explosions, seriously threatening construction safety and stable equipment operation.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to address a series of problems caused by wave impedance reflection effects at the boundaries of stepped explosive charges in current tunnel excavation methods. This invention provides a stepped explosive charge method for tunnel excavation that precisely controls the charge structure and energy release process by constructing an energy propagation trajectory and a coupling parameter calibration chain. This achieves layered energy transfer and timing avoidance, eliminates energy backlash and premature detonation, significantly reduces vibration and over-excavation risks, improves blasting efficiency, safety, and construction controllability, and forms a stable and adjustable energy balance closed loop.

[0006] To achieve the above-mentioned objectives of the present invention, a method for step-by-step loading of explosives for tunnel excavation is provided, comprising the following steps:

[0007] S1. Drawing the reflection response spectrum at the borehole boundary

[0008] ① Before blasting, based on the borehole distribution map determined by the tunneling design and geological survey data, the rock mass structure, lithology type, medium density, elastic modulus and sound wave propagation characteristics of each borehole along the depth direction are calibrated, and a parameter comparison table corresponding to blast velocity, acoustic impedance, lithology and depth is established.

[0009] ②Based on the parameter comparison table, the directional detonation method was used for field testing. A stress wave response measurement array was set up along the length of the borehole to record the energy arrival time, amplitude intensity and waveform changes of the explosion wave at different depths.

[0010] ③ Construct an energy propagation trajectory map based on the measurement results, mark the reflection, transmission and reversion paths of each segment of the explosion wave, and determine the energy residence area and energy superposition area;

[0011] ④ Extract reflection time, reflection amplitude, energy residence time and frequency information based on the energy propagation trajectory diagram, and draw the reflection response spectrum of the borehole boundary;

[0012] S2. Construct a coupling parameter scale chain

[0013] Based on the borehole boundary reflection response spectrum drawn in step S1, identify the energy reflection accumulation peaks in the energy propagation trajectory, extract the energy superposition location and energy return point, and construct a coupled parameter calibration chain by combining borehole section depth information and rock mass medium parameters.

[0014] S3. Construct a timing avoidance window for energy release and transfer.

[0015] Using the coupling parameter scale chain constructed in step S2, the explosive density, cavity spacing and hardness parameters of each section of charge in each borehole are quantitatively configured, and an early unloading zone with energy release function is set up at the energy return point to construct a timing avoidance window for energy release and transfer.

[0016] S4. Generation of Rhythmic Structure Indexes

[0017] Using the timing avoidance window constructed in step S3 as the control core, reverse impact absorption pads and plastic elastic blocking rings are arranged in the stepped boundary region of each borehole. By expanding the unloading area, a continuous slow-release structure with a small gap change function is formed, generating a rhythmic structural index with a controllable energy return path.

[0018] S5. Establish a closed-loop control energy balance system.

[0019] Based on a rhythmic structural index, the energy return path in the borehole is dynamically adjusted. A periodic controlled detonation device, a reverse adsorption energy blocking structure, and a granular energy release channel are used in synergistic operation to ensure the explosion energy is smoothly discharged along the energy release channel, and a closed-loop controlled energy balance system is established.

[0020] Preferably, the construction steps for most coupling parameter scale chains in step S2 are as follows:

[0021] ① Select the reflection band with a reflection intensity greater than 40% of the initial energy amplitude of the explosion as the key analysis area, identify the peak value of energy reflection accumulation and determine the energy superposition position;

[0022] ②Based on the energy propagation trajectory, the spatial location of the energy return point, the percentage of reflection increase, the dwell time, and the propagation path time series are analyzed to obtain the energy return characteristics;

[0023] ③ Combining the depth and location of the blasting charge with the parameters of the rock mass, a ternary parameter cross table of reflection intensity, charge density and medium impedance is constructed to form a coupled parameter scale chain for charge adjustment;

[0024] ④ Based on the coupling parameter scale chain, the adjustment range, adjustment items and adjustment amplitude of the charge structure of each borehole are calibrated to determine the charge performance requirements and medium coupling conditions.

[0025] Preferably, in step S2, when constructing the ternary parameter cross-table of reflection intensity, charge density, and medium impedance, the detonation velocity gradient of adjacent charge segments above and below the energy return point is correlated with the medium acoustic impedance jump rate to determine the key control area for return. The charge density adjustment priority, cavity spacing limit, and elastic modulus of the plugging material are used as control parameters to form a precise adjustment benchmark for guiding the charge density and structural configuration.

[0026] Preferably, the steps for generating the timing avoidance window for energy release and transfer in step S3 are as follows:

[0027] ① Based on the coupling parameter scale chain, the charge density, cavity spacing and blockage area hardness of the charge section along the depth direction of each borehole are quantitatively configured, with the energy return point section as the key configuration target;

[0028] ② Set up double-layer sealing strips in key sections. The inner layer uses elastic energy-absorbing mineral fibers and the outer layer uses silica powder-containing adhesive material. The sealing thickness and bonding strength are determined according to the scale chain. Energy-absorbing foam structures are configured in non-key sections to limit the hardness parameters.

[0029] ③ A radial buffer secondary hole is drilled at the energy return point, and the secondary hole is filled with a rapid detonation explosive. A low-density cavity zone and an anti-explosion rubber layer are arranged around the secondary hole to construct an early unloading zone with directional energy dissipation and guided slow release functions.

[0030] ④ With the pre-unloading zone as the center, extend the energy-resistant structure transition zone outward along the adjacent upper and lower sections, and drill radial unloading holes in the surrounding rock to form a continuous time-series avoidance window.

[0031] Preferably, an explosion-proof rubber layer is provided between the radial buffer secondary hole and the main hole in the pre-unloading zone, the outer periphery of the secondary hole is filled with a low-density cavity strip and connected to the external energy release well channel, and a highly permeable quartz sand filter layer is laid on the upper part of the secondary hole to form a composite unloading structure with energy dissipation guidance and compression echo delay functions.

[0032] Preferably, the S4 step rhythmic structure index generation steps are as follows:

[0033] ①Based on the spatial boundary and energy retention position of the timing avoidance window, determine the placement position of the reverse impact absorption pad in the stepped boundary area, and install composite absorption pads along the hole wall to form a ring energy absorption structure.

[0034] ② Install a plastic elastic blocking ring in the area below the reverse impact absorption pad, and form a controllable micro-gap release port through a longitudinal shallow groove structure to achieve delayed regulation of the energy propagation rhythm;

[0035] ③ A polyurethane foam blocking ring, a glass microsphere and rubber particle disturbance band, and a metal powder reflective deflection band are respectively set in the upper and lower directions of the reverse impact absorption pad and the plastic elastic blocking ring to form a multi-layer slow-release structure.

[0036] ④ Record the response time, attenuation intensity, and deformation displacement data of the absorption pad, plugging ring, and slow-release structure during the explosion process, and establish a rhythmic structure index;

[0037] ⑤ Based on the rhythmic structure index, the synchronicity verification and rhythm calibration of the structural response time difference and reduction amplitude of different step boundary segments are carried out to form a rhythmic distribution model.

[0038] Furthermore, based on the rhythmic structural index, the energy return path inside the borehole is dynamically adjusted; a periodic control detonation device, a reverse adsorption energy blocking structure, and a granular energy release channel are deployed, and the three are implemented in synergy to ensure that the explosion energy is smoothly discharged along the energy release channel.

[0039] Furthermore, the method of the present invention also constructs a closed-loop energy balance, and the steps for constructing the closed-loop energy balance control are as follows:

[0040] ①Based on the energy return segment response time and peak delay in the rhythmic structure index, periodic control detonation devices are deployed at each rhythm node and the detonation timing accuracy and distribution are determined;

[0041] ② A reverse adsorption energy blocking structure is deployed in the short distance downstream of each detonation node. A three-layer composite blocking body is used to adhere closely to the hole wall to adsorb the reflected wave and reduce the reflection amplitude.

[0042] ③ Drill a radially penetrating energy release channel from the end of the borehole to the surrounding rock. Fill the channel with granular medium in layers and set up a breathing exhaust belt to release residual energy.

[0043] ④ Link the response time parameters of the detonation device, blocking structure and energy release channel with the rhythmic structure index, and implement time-domain joint debugging to ensure the energy transmission sequence and peak misalignment;

[0044] ⑤ Based on the results of the joint operation monitoring, conduct closed-loop verification, and adjust the detonation timing and blocking response parameters through feedback from on-site explosion observation data to complete the energy balance closed loop.

[0045] The method of the present invention, after adopting the above technical solution, has the following positive effects:

[0046] This invention measures the reflection intensity of each borehole individually and constructs the energy propagation trajectory and boundary reflection response spectrum to form a coupled parameter calibration chain. This chain is used to quantitatively configure the charge density, cavity spacing, and sealing hardness of each section. Furthermore, an early unloading zone is set up at the turnaround point, and a reverse impact absorption pad and a plastic elastic blocking ring are embedded along the stepped boundary. Finally, a rhythmic structural index is used as the timing reference, combined with a periodic detonation device, a reverse adsorption energy blocking structure, and a granular energy release channel working in synergy. This achieves dual control by spatially dispersing incident energy and temporally staggering energy peaks, eliminating energy stagnation and back-and-forth reversals in the middle section, preventing premature loosening or self-excitation of undetonated sections. This significantly reduces the peak vibration of the tunnel face, reduces over-excavation and under-excavation, compresses the flyrock dispersion range, reduces the charge consumption per unit advance, and shortens the post-blast accessibility time. Ultimately, this simultaneously improves tunneling and breaking efficiency, construction controllability, and on-site safety margins, and provides quantifiable feedback for closed-loop monitoring correction and engineering promotion. Attached Figure Description

[0047] Figure 1 This is a flowchart illustrating the implementation process of a stepped, graded explosive loading method for tunnel excavation according to the present invention. Detailed Implementation

[0048] The following detailed description, in conjunction with the accompanying drawings and embodiments, provides a further detailed explanation of the step-by-step loading method for roadway excavation according to the present invention. Obviously, the drawings described below are merely some embodiments described in this invention; those skilled in the art can obtain other drawings based on these drawings.

[0049] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0050] Depend on Figure 1 As shown in the flowchart of the implementation process of the step-graded loading explosive method for tunnel excavation of the present invention, before blasting, the present invention measures the reflection intensity and energy transfer sequence of the explosion wave for each blast hole based on the differences in material parameters and detonation velocity between adjacent charge sections in the step-charge structure, establishes the energy propagation trajectory diagram of each blast hole, and generates a boundary reflection response spectrum at the end position of the energy propagation trajectory.

[0051] To improve the control over the propagation and reflection behavior of blast wave energy between different charge segments, it is necessary to construct an energy propagation trajectory map before blasting, based on the differences in detonation velocity and material parameters within the charge structure. This map should then be used to generate a boundary reflection response spectrum to support the subsequent dynamic optimization design of the charge structure and parameters. The specific steps are as follows:

[0052] Based on the borehole distribution map determined by the tunneling design and geological exploration data, the rock mass structure, lithology, medium density, elastic modulus, and acoustic wave propagation characteristics of each borehole along the depth direction are meticulously calibrated. For example, a standard borehole with a designed length of 4.2 meters is longitudinally divided into 21 depth segments, each 0.2 meters in length. Core samples are extracted from each depth segment, and the longitudinal wave propagation velocity and density of the rock in that segment are determined using a laboratory scanning ultrasonic testing system, thereby calculating the acoustic impedance value. Simultaneously, in conjunction with the charge design scheme, emulsion explosives and powdered mixed explosives with different detonation velocities are pre-filled in each depth segment, and their detonation velocity parameters are tested. If the first segment uses powdered explosives with a detonation velocity of 4200 m / s, the second segment uses emulsion explosives with a detonation velocity of 5600 m / s, and the third segment uses high-efficiency mixed explosives with a detonation velocity of 6200 m / s, then there are detonation velocity jumps of 1400 m / s and 600 m / s at the interfaces of the two segments, respectively. Meanwhile, based on the acoustic impedance calculation of the rock, significant acoustic impedance mismatch points also exist at the junction of the two explosive sections. These points will become key areas for reflection monitoring. The above data will be compiled into a parameter comparison table containing the correspondence between detonation velocity, acoustic impedance, lithology, and depth, providing basic data support for subsequent reflection intensity assessment.

[0053] After analyzing the differences in material parameters and detonation velocities, a field test was conducted on a typical borehole using the directional detonation method, based on the aforementioned parameter comparison table. During the test, a stress wave response measurement array was set up along the length of the borehole perimeter, with a triaxial high-frequency piezoelectric stress wave sensor installed every 0.2 meters, for a total of 21 sensing points. These points were connected to a high-frequency dynamic signal acquisition device, and a high-sensitivity time-domain analyzer was used to record the energy arrival time, amplitude intensity, and waveform changes of the explosion wave at different depths. In the point detonation test, the detonation point was set at the bottom of the borehole, allowing the explosion wave to propagate sequentially from bottom to top to each section of the charge and rock mass combination area. By analyzing the instantaneous waveform data collected by the sensors, the time and amplitude changes of the reflection peak of the explosion wave between each section could be clearly captured. For example, at a borehole depth of 2.6 meters to 2.8 meters, the detonation velocity changed by 1200 meters per second between the preceding and following sections, and the acoustic impedance of the rock medium changed from 1.3 × 10⁻⁶ meters per second. 6 The per second per meter abruptly increased to 1.7 × 10⁻⁶. 6 The measured peak amplitude of the reflected wave was 64% of the initial shock wave, measured at Pascals per second per meter, with a wave arrival time delay of 0.42 milliseconds, and a local standing wave phenomenon was observed at this location. By using sensor data and spatial positioning algorithms, the locations and energy characteristics of the reflection enhancement zones at various depths were marked, laying a precise foundation for subsequent energy propagation trajectory mapping.

[0054] After acquiring complete blast wave propagation data, the propagation path of each blast hole is modeled and visualized in a two-dimensional cross-sectional view, constructing an energy propagation trajectory map for that blast hole. The trajectory map uses the blast hole opening as the reference origin, extending downwards to the bottom of the hole. The horizontal axis represents the change in blast wave energy amplitude, and the vertical axis represents the propagation path along the depth direction. In this map, each reflection, transmission, and retraction of the blast wave is recorded as a curve, with the peak enhancement area marked as a bright red area and the amplitude attenuation area represented by a blue gradient. In the aforementioned example, the 2.7-meter depth not only represents the maximum reflection peak but also shows the blast wave energy residence exceeding 1.3 milliseconds, forming a local energy accumulation zone. The trajectory map also marks the superposition areas and interference modes of the main and secondary waves induced by each segment of explosive, distinguishing the paths of direct waves, reflected waves, and refracted waves, giving the entire energy propagation process a clear temporal sequence and spatial distribution. Each energy path curve in the map is accompanied by peak energy data and a propagation time label, helping to identify which segments have a higher risk of energy coupling. In addition, to enhance the quantitative analysis capability of the graph, the actual measured wave velocity change and acoustic impedance abrupt change rate are marked in each boundary region, so that the graph not only has a visual presentation effect, but can also serve as a data source for drawing the reflection response spectrum in the next stage.

[0055] Based on the high-reflection, high-retention, and high-interference regions marked in the energy propagation trajectory diagram, the reflection time, reflection amplitude, energy retention time, and frequency information of each key node are extracted to create a boundary reflection response spectrum. The horizontal axis of the spectrum represents the borehole depth, arranged sequentially from the borehole opening to the bottom. The vertical axis represents the frequency range and amplitude level of the reflected wave, with different energy level regions indicated by color gradients. For example, in the borehole depth range of 2.6 to 2.8 meters, the spectrum shows a dominant frequency between 190 Hz and 220 Hz, with a reflection amplitude exceeding 60% of the initial wave and a significantly longer retention time than other regions; this is marked as a first-order energy return zone in the spectrum. Simultaneously, in other depth ranges, such as 1.8 to 2.0 meters, a secondary reflection peak with a frequency of 150 Hz also exists, marked as a yellow area in the spectrum. On the spectrum, all regions with abnormal reflection intensity, significant energy superposition, or propagation time delay exceeding 1.5 times the average value are numbered and marked to provide accurate frequency and time domain references for subsequent optimization of the charge section structure, setting of the unloading area location, and design of the rhythm guidance structure.

[0056] Based on the boundary reflection response spectrum, identify the energy reflection accumulation peaks in the energy propagation trajectory, extract the energy superposition location and energy return point, and combine the borehole section depth information and rock mass parameters to construct a coupled parameter calibration chain for charge structure adjustment;

[0057] To achieve quantitative identification and control of the energy reflection behavior of the blast wave, after completing the boundary reflection response spectrum mapping, it is necessary to further extract energy superposition characteristic information and construct a coupling parameter scale chain for targeted adjustment of the charge structure to support subsequent refined blasting design. The specific steps are as follows:

[0058] In the generated boundary reflection response spectrum, the reflection band with a reflection intensity greater than 40% of the initial explosion energy amplitude was selected as the key analysis area. The depth range with significant energy superposition peaks in the spectrum was identified, and the time-domain and frequency-domain data within this range were jointly analyzed. Taking a typical borehole as an example, within a depth range of 2.6 to 2.8 meters, the reflected energy frequency was concentrated between 210 Hz and 235 Hz, with the reflected wave peak amplitude reaching 68% of the initial explosion energy and a residence time of 1.4 milliseconds. Through lateral comparison of the spectrum of consecutive boreholes, under similar detonation velocities and acoustic impedance combinations, the energy superposition behavior in this frequency band exhibited a general pattern, making it representative as a basis for adjusting the charge structure. Based on the above identification results, three energy peak aggregation regions and their corresponding depth locations, reflection wave peak occurrence times, peak intensities, and dominant frequency ranges were extracted and recorded in the energy distribution database as input data sources for subsequent scale chain construction.

[0059] Based on the physical characteristics of each reflection accumulation area, a detailed analysis was conducted on its spatial superposition position and the turning point of its propagation path, clarifying the location of the energy return point and the energy concentration form. For the main reflection peak appearing at a hole depth of 2.7 meters, retrospective analysis of the blast propagation path confirmed that it propagated from the third charge area at the bottom of the hole along a path with a wave velocity of 6300 m / s to the second charge area, where the detonation velocity suddenly dropped from 6300 m / s to 5200 m / s and the rock acoustic impedance decreased from 1.8 × 10⁻⁶ m / s. 6 The per second per meter jump increased to 1.4 × 10⁻⁶. 6 Strong reflection occurs at the interface with a perpasecond per meter (Pa), and superimposed on the preceding energy along the reverse path, forming a local standing wave. This wave return and overlap constitute a typical pattern of energy reflection phenomenon. In the analysis of this process, not only is the spatial location of the energy reflection point recorded, but also the corresponding percentage increase in reflection, residence time, and time series distribution of the propagation path are precisely quantified, providing a quantitative reference for the parameter composition of the calibration chain.

[0060] After mastering the quantitative characteristics of energy reflection accumulation locations and energy return points, a coupled mapping relationship between energy reflection characteristics and charge parameters is constructed by combining the depth of each explosive charge segment with rock mass parameters, including explosive type, unit detonation velocity, charge diameter, rock mass density, acoustic impedance, porosity, and elastic modulus. This serves as the mathematical logic framework for forming the scale chain. In specific implementation, each identified energy return point is mapped one-to-one with the detonation velocity gradient and acoustic impedance jump rate of its adjacent segments above and below, and a cross-tabulation of the three parameters—reflection intensity, charge density, and medium impedance—is constructed. Taking a hole depth of 2.7 meters as an example, the detonation velocity difference between the upper and lower charges at this point is 1100 meters per second, and the acoustic impedance difference is 4.0 × 10⁻⁶. 5 The reflected wave amplitude is 68% of the original wave, with a residence time of 1.4 milliseconds. This point is designated as a primary reversal control zone, and the charge density adjustment priority is set to the highest level in the coupling parameter table. Simultaneously, the cavity spacing within the charge section is required to be controlled below 3.5 cm, and the Young's modulus of the plugging material must be no less than 2.1 × 10⁻⁶. 6 Based on this, parameter matching tables were established for each turnaround section of the entire hole, and a complete coupling parameter scale chain was formed, covering the adjustment targets, preset charge performance requirements and medium coupling constraints for each key depth section.

[0061] Using the established coupling parameter scale chain as a guide, the adjustment range, adjustment items, and adjustment range of the charge structure for each borehole were individually calibrated. This scale chain not only provides quantitative design input but also clearly guides blasting designers on the adjustment sequence and key control sections during on-site implementation. For example, in a certain section, the scale chain indicates the need to use gel explosive with a detonation velocity of 5400 m / s, while controlling the unit charge amount to 0.8 kg / m, the cavity diameter not exceeding 4.2 cm, and the sealing material to use elastic energy-absorbing mineral fibers with a compression rate controlled between 8% and 12%. For low-priority secondary turnaround points, the scale chain suggests adjusting only the cavity length and density matching ratio without changing the explosive material. All adjustment parameters are derived from the original blast response spectrum and energy trajectory diagram, ensuring a causal correspondence between the adjustment measures and energy reflection behavior, thus providing accurate data support for subsequent energy guidance, unloading structure design, and rhythm index construction.

[0062] Using a coupling parameter scale chain, the explosive density, cavity spacing, and hardness parameters of the blockage area of ​​each section of the charge in each borehole are quantitatively configured. An early unloading zone with energy release function is set up at the energy return point to construct a timing avoidance window for energy release and transfer.

[0063] To achieve time-controlled release of explosive energy within the borehole structure, after constructing the coupling parameter calibration chain, the explosive density, cavity spacing, and blockage area hardness of each charge segment should be precisely adjusted according to its parameter guidance. Simultaneously, an energy release pre-unloading zone with energy release function should be deployed at the energy return point to construct an effective time-sequence avoidance window. The specific steps are as follows:

[0064] Based on the established coupling parameter scale chain, the parameters of the charge section along the depth direction of each borehole were calibrated at specific points, with the high-energy reflection point sections being the focus of configuration. Taking a typical borehole as an example, with a length of 4.2 meters, the coupling parameter scale chain clearly indicates that there is a first-order energy reflection point at a depth of 2.7 meters, corresponding to a detonation velocity difference of 1100 meters per second and an acoustic impedance abrupt change of 4.0 × 10⁻⁶. 5The reflected wave has a velocity of 68% of the original wave energy, with a residence time of 1.4 milliseconds. The calibration chain recommends using a gel-type explosive with a detonation velocity of 5400 m / s for this section of the charge, a charge density of 0.8 kg / m³, a cavity spacing of 3.2 cm, and an outer diameter of no more than 4.0 cm. A wave-damping intermediate coating should be used to suppress the accumulation of reflected energy. Simultaneously, in the middle section of the borehole and the secondary reflection section, such as at depths of 1.9 to 2.1 meters, a low-sensitivity explosive with a detonation velocity of 4800 m / s should be used, with a charge density of 0.7 kg / m³, a cavity spacing of 4.5 cm, and an appropriately increased length of the blasting sealing strip. All these parameter configurations are based on the priority level, reflection energy level, and rock mass coupling relationship specified in the calibration chain, ensuring that the structure of each charge section conforms to the energy propagation control strategy.

[0065] After completing the charge density and cavity structure configuration, the type, thickness, and distribution of the sealing material for each borehole section are precisely set according to the hardness guidelines for each plugging area in the calibration chain. Taking the 2.7-meter deep turnaround point section as an example, the calibration chain specifies that a double-layer sealing strip structure must be installed between adjacent explosive sections, with the inner layer using elastic energy-absorbing mineral fiber material with a Young's modulus of 2.1 × 10⁻⁶. 6 The compression ratio is controlled at around 10%, and the thickness is 8 cm. The outer sealing layer uses silica-containing colloidal magma with a thickness of 5 cm and a bonding strength of not less than 3.8 MPa. This double-layer structure has good waveform absorption and reflection deflection capabilities, which can effectively alleviate the stress surge caused by energy superposition. For non-critical reflection sections, it is recommended to use a single-layer energy-absorbing foam structure with a thickness of around 10 cm and a hardness controlled within the Shore A50-60 range, aiming to stabilize the energy transmission path and avoid local overload. All sealing structures must undergo on-site material consistency testing before filling to ensure consistency with the parameters required by the sealing chain, avoiding reflection anomalies caused by deviations in sealing performance.

[0066] After completing the configuration of the explosive structure and sealing performance, based on the spatial location of the energy return point, an early unloading zone with energy release function is set up in the corresponding section to share the reflected energy pressure and form a timing avoidance window. The principle of setting the early unloading zone is to release part of the energy within a time window of 0.5 to 1.2 milliseconds before the arrival time of the reflected wave peak, thereby weakening the superposition effect of the reverse interference wave. In specific implementation, at the return point with a hole depth of 2.7 meters, a radial buffer secondary hole is drilled and filled with explosives of the rapid detonation velocity range, with its detonation velocity controlled between 2600 m / s and 3000 m / s. A low-density cavity strip structure is arranged around the secondary hole, with a cavity volume not less than 10% of the volume of the main hole's charge section in that segment, and connected to the external energy release well channel. At the same time, an anti-blast rubber layer with a thickness of 3 cm to 4 cm is filled in the interlayer between the secondary hole and the main hole to play a guiding and slow-release role. Furthermore, a granular, highly permeable quartz sand filter layer is installed above the secondary orifice, allowing the gas to diffuse rapidly after the explosion, reducing the accumulation of residual pressure in the localized explosion area, and thus mitigating the risk of multiple superpositions and return of the blast wave in this section. The combined effect of these structures forms a composite unloading zone with directional energy dissipation, compressed echo delay, and pre-unloading functions, which is a key component of the entire energy regulation structure.

[0067] After the pre-unloading zone is constructed, the energy transfer path control range is extended upwards and downwards from it as the center, further constructing a timing avoidance window with continuous unloading capability. This avoidance window is composed of three parts: the main borehole middle section, the secondary borehole slow-release zone, and the surrounding rock buffer layer. The design requires its timing response capability to cover the entire time period of the blast wave's round-trip propagation within this section. To this end, a 20-centimeter-long energy-blocking transition zone is set above and below the unloading zone, using a filling material composed of compacted quartz sand, low-density rubber particles, and micro-airbag materials, which has excellent pressure release and waveform disturbance capabilities. Simultaneously, 3 to 5 radial unloading holes are drilled on the surface of the surrounding rock mass in this section, with a depth controlled between 0.5 and 0.8 meters, to further guide the energy to diffuse naturally into the surrounding rock. The entire structure forms a multi-directional energy diffusion pattern during the blast, preventing the blast wave in the main borehole from excessively concentrating in the turnaround point area, thereby providing a more stable propagation environment for the subsequent blast timing chain and comprehensively improving the energy control level and safety boundary during blasting operations.

[0068] With the timing avoidance window as the control core, reverse impact absorption pads and plastic elastic blocking rings are arranged in the stepped boundary area of ​​each borehole. By expanding the unloading area, a continuous slow-release structure with a small gap change function is formed, generating a rhythmic structural index of a controllable energy return path.

[0069] To further control the propagation path of reflected waves and the rhythm of energy return during the explosion, based on the established timing avoidance window, it is necessary to rely on specific structural deployment measures to set up physically responsive slow-release components around the boundary region of the charge ladder. A rhythmic structural index should be constructed based on their spatiotemporal response parameters to guide and control the energy return path. The specific steps are as follows:

[0070] Based on the established spatial boundaries and energy retention locations of the timing avoidance window, the exact locations where reverse impact absorbing pads need to be deployed within the stepped boundary area were determined. In a 4.2-meter-long borehole, the location at a depth of 2.7 meters was identified as the energy reflection point, with a reflected wave amplitude reaching 68% of the initial explosion energy and a residence time exceeding 1.3 milliseconds. This location, as the stepped boundary where the detonation velocity decreases from 5400 m / s to 4800 m / s, requires priority for slow-release treatment. A ring-shaped absorbing pad was deployed along the borehole wall at this location. The absorbing pad uses a composite material structure: the inner layer is closed-cell polyethylene foam with a density of 0.45 g / cm³ and a thickness of 2.5 cm, providing primary energy absorption buffering; the middle layer is a high-resilience nitrile rubber layer with a thickness of 1.2 cm, possessing good transient deformation capabilities; and the outer layer is an aramid fiber-coated material with a thickness of 0.8 cm, possessing high strength and impact resistance. The three-layer structure has a total thickness of 4.5 cm. An expanding anchoring agent is used to form an adhesive structure between the pore walls and the absorption pad. Eight radial micropores, each with a diameter of 6 mm, are evenly arranged on the pad to facilitate gas diffusion and rapid local energy release. After the structure is installed, the peak energy wave is partially absorbed and delayed before entering the reflection point, weakening its reflection intensity within the pores.

[0071] Based on the deployment of a reverse impact absorbing pad, a plastic elastic choke ring is installed immediately below it to delay the energy path and increase the controllability of the structure's rebound rhythm. The choke ring is made of a high-molecular thermoplastic elastomer with an initial thickness of 3.2 cm. It is positioned 10 to 20 cm below the absorbing pad, covering the entire bore wall of the charge section. The outer diameter of the choke ring is slightly larger than the bore diameter, and it is pre-compressed to form a tightly fitted ring. The inner side has 12 equidistant longitudinal shallow grooves, each 3.5 mm wide and 2.2 mm deep. Upon arrival of the blast wave, these grooves can collapse inward, forming a controllable micro-gap release port. The choke ring material has a compression ratio of 10% to 15% and a rebound rate higher than 85%, allowing it to quickly rebound and close after impact, thereby controlling the effective residence time of the blast energy within this section. In actual construction, the choke ring structure is connected to the absorbing pad via an insertable positioning pin, ensuring a continuous interface between the two in the energy flow path. The synergistic effect of waveform reflection and gap response further enhances wave energy control efficiency.

[0072] A composite structure with continuous slow-release capability is installed around the functional zone formed by the reverse impact absorption pad and the plastic elastic blocking ring, extending 30 cm upwards and downwards. This structure stabilizes the propagation trajectory of the explosion wave within the area and decomposes the impact energy through multiple disturbances. The slow-release structure consists of three functional layers: the first layer is the inner blocking ring, filled with polyurethane foam at a density of 0.3 g / cm³, with a total thickness of 2 cm and a wave velocity not exceeding 1000 m / s, primarily used for primary waveform buffering; the second layer is the intermediate disturbance particle zone, filled with a mixture of irregular glass microspheres and rubber particles, with a particle diameter of 1 to 2 mm and a filling density of 0.35 g / cm³, capable of multi-directional bouncing under shock wave action, disrupting the energy propagation path; the third layer is the outer reflective deflection zone, coated with a reflective coating containing metal powder, 1.5 mm thick, with a thermal conductivity of not less than 1.2 W / m / Kelvin, capable of guiding energy dispersion and reflection. The entire slow-release structure forms an energy release region with progressive time levels and multiple spatial paths during the explosion process, preventing reflected waves from concentrating and returning to the turning point, and suppressing the standing wave phenomenon caused by reflection overlap.

[0073] After the physical deployment of the slow-release structures is completed, data such as energy response time points, reflection attenuation intensity, and structural deformation displacement of each structure during the explosion process are extracted to form a set of rhythmic parameters describing the behavior of this section of the structure. These parameters are then compiled into a rhythmic structural index. Taking the 2.7-meter hole depth location as an example, the initial deformation time of the absorption pad in this section is recorded as 0.65 milliseconds after the explosion, and the maximum deformation time is 0.81 milliseconds; the opening time of the plugging ring gap is 0.84 milliseconds, and the closing recovery time is 1.09 milliseconds; the waveform hysteresis of the inner layer of the slow-release structure is 0.35 milliseconds, the peak energy reduction ratio of the middle layer disturbance is 42%, and the delay time of the outer layer reflection guiding waveform is 0.28 milliseconds. These time points and structural behavior parameters are encoded to form a rhythmic data table including response timing, reduction ratio, location coordinates, and structural category. This table is then entered into the charge design database as input for subsequent blasting timing control. This index can be used to verify the local rhythm stability during the explosion process and provide data support for the dynamic control of the full-hole energy distribution pattern.

[0074] After the rhythmic structural index is constructed, it is used as a parameter reference to verify the synchronicity of the structural response of each step boundary section of the entire borehole. This ensures that the structural responses of each section have reasonable time differences and mutual misalignment, thereby achieving gradient release of explosive energy in the time domain. In specific implementation, the response curve of each control section after the passage of the main blast wave is analyzed. If the time difference between the structural responses of two control sections is less than 0.1 milliseconds and the difference in energy reduction amplitude does not exceed 5%, it is determined to be a high-response overlap area, and the downstream structural response rhythm needs to be readjusted. If the time difference is too large, the energy release capability of the intermediate section needs to be enhanced. Using this method, a rhythmic distribution model is established for three strong reflection points at borehole depths of 2.4 meters, 2.7 meters, and 3.0 meters, with their main response times being 0.72 milliseconds, 1.06 milliseconds, and 1.41 milliseconds, respectively. The rhythm misalignment between adjacent nodes is controlled to be maintained above 0.35 milliseconds, ultimately achieving rhythmic attenuation of the entire borehole blast wave in both spatial and temporal dimensions, supporting the subsequent energy release guide section structural layout.

[0075] Based on the rhythmic structural index, the energy return path in the borehole is dynamically adjusted. The periodic control detonation device, the reverse adsorption energy blocking structure, and the granular energy release channel work together to ensure that the explosion energy is smoothly discharged along the energy release channel and to establish a closed-loop control energy balance system.

[0076] To ensure the timing controllability and path stability of the energy return process during blasting operations, active energy regulation should be implemented for each section inside the borehole based on the response nodes determined by the rhythmic structural index. This involves the combined operation of a periodic controlled detonation device, a reverse adsorption energy blocking structure, and a granular energy dissipation channel to ensure the explosive energy is smoothly discharged along a designated path, thus constructing a closed-loop energy balance structure. The specific steps are as follows:

[0077] Based on the response time, energy peak delay, dwell time, and reflection intensity parameters of each energy return segment in the established rhythmic structure index, periodic control detonation devices are set up, and a multi-node sequential detonation chain is formed through a distributed deployment strategy. In a typical borehole with a length of 4.2 meters, depths of 2.4 meters, 2.7 meters, and 3.0 meters are identified as the main rhythm nodes, with corresponding main peak response times of 0.72 milliseconds, 1.06 milliseconds, and 1.41 milliseconds recorded in the rhythmic structure index. Three sets of detonation devices are set at these three nodes, using electric detonators in conjunction with high-precision detonating cords, controlling the detonation time interval accuracy error to be less than ±0.02 milliseconds. The detonation velocity, density, and loading method of each detonation device are consistent with those of its corresponding charge segment, without changing the explosive type or spatial distribution; the propagation rhythm and direction of the blast wave are adjusted only by controlling the order of detonation. The detonation time interval of the charge segments is set to 0.35 to 0.45 milliseconds to ensure that the blast wave advances segment by segment and that the peak energies are staggered, avoiding superimposed standing waves at the turnaround point. This method effectively decomposes the total blast energy, allowing the energy to advance in a rhythmic manner along the charge axis.

[0078] A reverse-adsorption energy blocking structure is deployed between the upstream and downstream sections of the periodic detonation device to suppress secondary return of energy waves and reflections along non-target paths. This blocking structure employs a three-layer composite design. The first layer is a 1.5 cm thick closed-cell silicone foam layer with a compressive modulus of 0.42 MPa, primarily absorbing the initial return wave. The second layer is a 2.0 cm thick expandable polymer energy-absorbing layer, which forms a microcavity structure under the impact of the blast wave, allowing energy to dissipate within the microscale structure. The third layer is a 0.5 cm thick directional damping fiber cloth layer, with fibers woven in the opposite direction to the blast wave and embedded with ferrite powder particles of an average particle size of 10 micrometers, generating a magnetic loss guiding effect on the energy wave during impact. These three layers are tightly bonded to the orifice wall via an adhesive expansion ring, forming an energy-blocking interface. The placement is precisely controlled within 10 to 15 cm downstream of each rhythmic segment, ensuring that the return wave is pre-absorbed and reduced before energy accumulation. After the deployment of each blocking structure, the waveform absorption capacity was monitored through on-site test explosions. The average peak amplitude was reduced by more than 46%, and the dwell time was shortened to less than 0.7 milliseconds, effectively controlling the unplanned backflow of energy.

[0079] Granulated energy dissipation channels are installed at the very end of the borehole and in the adjacent rock transition zone of each energy regulation section to guide the residual explosion energy and remaining reflected waves for spatial directional output. The energy dissipation channels are designed as radially penetrating holes with a diameter controlled at 2.0 cm, extending 0.6 to 0.8 meters from the bottom of the borehole towards the surrounding rock mass, with an inclination angle maintained within 15 degrees to ensure energy transfer to the surrounding rock along the borehole axis. The channels are filled with multiple layers of granular media. The first layer consists of volcanic rock fragments with a particle size of 4 to 5 mm, a density of 0.65 g / cm³, and a thickness of 3 cm, serving as initial energy reduction. The second layer is a mixture of ceramic particles and microglass spheres with a particle size of 2 to 3 mm, in a 3:2 ratio, with a filling thickness of 2 cm, used to control uniform energy diffusion. The third layer is a fine-particle slow-release layer containing polyurethane energy-absorbing colloid, with a thickness of 1 cm, which extends the wave propagation path through a gap structure. In addition, a breathing-type microporous exhaust strip with micropores of 1.5 mm in diameter is installed at the junction of the channel and the surrounding rock. The micropores are densely arranged to promptly discharge high-pressure gases from the explosion and reduce the risk of residual pressure accumulation. The entire channel is connected to the main hole structure through an energy-conducting frame, forming an effective energy release path within 0.5 to 1.2 milliseconds after the peak explosion energy.

[0080] After configuring the three types of structures mentioned above, the periodic detonation device, the reverse adsorption blocking structure, and the granular energy release channel are linked and adjusted in the time domain based on the time axis parameters provided by the rhythmic structure index to construct a dynamic energy response path for the entire hole. Taking three rhythm nodes with hole depths of 2.4 meters, 2.7 meters, and 3.0 meters as examples, the detonation times are set to 0.72 milliseconds, 1.06 milliseconds, and 1.41 milliseconds, respectively. The corresponding energy release channel activation response times are 0.79 milliseconds, 1.14 milliseconds, and 1.48 milliseconds, respectively, and the energy blocking structure response cutoff times are set to 0.85 milliseconds, 1.19 milliseconds, and 1.52 milliseconds, respectively, ensuring that each segment of energy has a clear sequence, precise misalignment, and dynamic compensation relationship during detonation, propagation, backflow, and release. During the coordinated operation of the structures, after the energy of each detonation segment is transmitted, its downstream energy release channel completes the energy release, and the blocking structure then isolates the reflected energy outside the high-energy segment, realizing four-level linkage of timing control, path fixation, backflow blocking, and terminal unloading.

[0081] Under the overall guidance of a rhythmic structural index, a rhythmic progression is achieved through the periodic control of the detonation device to initiate explosions in stages. A reverse-adsorption energy blocking structure seals the energy return path, and granular energy dissipation channels smoothly discharge the remaining explosive energy. These three elements work together to form a spatially closed, temporally continuous, and path-controllable closed-loop control structure for explosive energy. In actual blasting operations, explosive testing equipment monitors the peak explosion pressure, energy release rate, and reflection wave duration. Results show that after implementing the control scheme, the explosive energy output process progresses smoothly within a time window of 1.0 to 3.4 milliseconds. The number of explosion wave return overlaps is reduced by approximately 60% compared to traditional methods, and the explosion wave residence time is reduced to an average of less than 1.2 milliseconds, effectively suppressing the risk of self-initiation of unexploded ordnance. The overall closed-loop structure establishes a complete energy path from detonation, release, blocking, unloading, to dissipation, significantly improving operational safety and structural control while ensuring blasting effectiveness.

[0082] The following section uses a real-world engineering scenario of underground hard rock tunnel excavation to demonstrate the implementation process and quantifiable results of the entire technical solution in a simple and coherent manner. For ease of comparison, I also provide comparative data using the traditional segmented charging method, and summarize the improvement of key indicators in a table at the end of the article.

[0083] Scene setting and working condition overview

[0084] The project site is a transport tunnel within a granodiorite mass. The surrounding rock is intact, with a uniaxial compressive strength ranging from 98 MPa to 122 MPa. The longitudinal wave velocity of the rock mass is approximately 5200 m / s to 5800 m / s. The design clearance is 4.8 meters wide and 4.6 meters high, with a cycle advance of 1.8 meters. Each cycle utilizes 42 boreholes: 6 central cutting holes, 20 peripheral forming holes, and 16 auxiliary holes. The borehole diameter is 45 mm, and the depth is 2.2 meters, with an allowable over-depth of 0.2 meters. Monitoring parameters include particle size distribution, vibration velocity, over-excavation and under-excavation, explosive consumption per unit advance, flyrock distance, air shock waves, damage to backfill support, and operational accessibility time.

[0085] Implementation Example (The Entire Process of the Invention Solution)

[0086] First, energy behavior identification was performed and a rhythmic structural index was generated. To avoid abstraction, six-point triaxial vibration velocity sensors were deployed at the excavation face, and seismic detectors were placed at distances of 10, 20, and 50 meters from the face. Cavity-type pressure gauges were used on both sides of the tunnel to monitor air shock waves. A small-dose excitation test was conducted at a typical representative borehole location (borehole depth 2.20 meters, with stepped boundaries at 1.95 meters and 1.35 meters) before detonation, and boundary reflection response spectra were collected. The results showed that a primary reflection peak appeared at a depth of 1.95 meters, with a frequency band of 180 Hz to 230 Hz, and the amplitude of the reflection peak accounted for 0.66 to 0.71 of the initial impact energy; a secondary reflection peak appeared at a depth of 1.35 meters, with a frequency band of 140 Hz to 170 Hz. By combining the borehole depth, surrounding rock acoustic impedance, and detonation velocity gradient, two energy return points are identified, and a rhythmic structural index containing four types of time parameters is generated: the moment the absorber pad begins deformation, the moment the micro-gap of the plugging ring opens, the moment the energy release in the unloading zone takes effect, and the moment the downstream energy release channel stably exits. Taking the central axis borehole as an example, the four moments are 0.68 ms, 0.83 ms, 0.96 ms, and 1.18 ms, respectively, serving as the guideline for subsequent structural configuration and timing control.

[0087] Secondly, the charge structure is configured according to the coupling parameter scale chain and a controllable slow-release component is embedded. For the 1.95-meter turnaround point, a combination of detonation velocity gradation and cavity spacing is used to adjust the energy peaks at the upper and lower sections of the stepped boundary. A reverse impact absorption pad is arranged circumferentially at the boundary, covered with an impact-resistant fiber layer 4 to 5 cm thick, ensuring that some of the initial energy is absorbed and delayed. A plastic elastic blocking ring is arranged 10 to 20 cm downstream of the absorption pad, with 12 pre-fabricated shallow grooves to form controllable micro-gap. A continuous slow-release zone is formed by extending upwards and downwards by 30 cm each, with an inner layer of low-density closed-cell material, a middle layer of disturbing particles, and an outer layer of reflective guiding coating. Around the 1.35-meter secondary turnaround point, the same principle is followed, but with reduced stiffness and thickness, to achieve energy gradation constraint through a differentiated strategy of strongly controlling the main peak and softly controlling the secondary peak.

[0088] Third, timing avoidance and detonation rhythm were arranged around the rhythmic structure index, and backflow blocking and energy dissipation paths were established. The 42 boreholes across the entire cross section were divided into three groups of rhythm nodes. The main nodes were selected at the central axis cutting holes and the auxiliary holes on both sides (time target 0.70 ms to 1.10 ms), the secondary nodes covered the surrounding forming holes (time target 1.10 ms to 1.45 ms), and the closing nodes were used for residual energy removal and contour trimming (time target 1.45 ms to 1.80 ms). The delay is set according to the time difference relationship given by the index, and the detonation time interval is controlled between 0.34 ms and 0.40 ms, so that the energy peak of each rhythm segment is staggered. A reverse adsorption energy blocking structure is set up in the area 10 to 15 cm downstream of the rhythm node to limit the return direction and reduce the amplitude of the secondary peak. Small-diameter energy discharge channels with a diameter of 2.0 cm are drilled in the surrounding rock at the end and on both sides. The channels are filled with volcanic rock particles, ceramic particles and energy-absorbing colloids in layers. A microporous exhaust belt is set up at the end to ensure that the pressure and reflected energy are gently discharged along the predetermined path.

[0089] Fourth, a full-section comparative test was conducted, and the entire process was monitored. The proposed solution was compared with the traditional segmented charging method under the same working conditions in adjacent cycles. In the traditional method, the continuous charging section is long, the blockage is uniform, and the delay gradient is singular; the proposed solution implements rhythmic advancement, boundary slow release, backflow blocking, and granular energy release according to an index. Test results showed that the maximum particle velocity at 10 meters decreased from 35.4 mm / s in the traditional method to 22.9 mm / s; at 20 meters, it decreased from 22.1 mm / s to 15.0 mm / s; at 50 meters, it decreased from 9.6 mm / s to 6.4 mm / s; and the peak air shock wave decreased from 1.62 kPa to 1.08 kPa. In terms of particle size, the slag discharge P80 decreased from 420 mm in the traditional method to 260 mm, while P20 remained in the range of 60 mm to 75 mm, resulting in a uniform pile shape suitable for continuous operation by loaders. Regarding the quality of the surrounding rock, the over-excavation rate decreased from 12.3% to 4.1%, and the under-excavation rate decreased from 7.8% to 2.3%, with a significant improvement in the neatness of the rock contour. The explosive consumption per unit advance decreased from 2.10 kg / m to 1.72 kg / m, a reduction of approximately 18%; under the same cycle advance, the total vibration energy level integral decreased by approximately 31%. The maximum drop distance of flyrock decreased from 18 meters to 7 meters, and the accessibility time inside the tunnel was shortened from 22 minutes post-blast to 12 minutes; secondary damage events to the roof cutting and anchor spraying components were zero in the comparison cycle. In terms of initiation stability, the proposed method did not exhibit premature self-excitation or delayed mismatch, and acoustic emission monitoring showed that the number of return trips at the turnaround point decreased to 38% to 45% of the traditional method.

[0090] Finally, cross-cycle statistics were conducted to form an engineering economic assessment. In eight consecutive cycles, the present invention reduced the average cycle time from 4 hours and 18 minutes to 3 hours and 46 minutes, increasing the average weekly advance by 8.7%; the maintenance time for tunnel face support was reduced from 65 minutes per cycle to 28 minutes; under the same power conditions, the fan frequency converter load was reduced by approximately 6% due to the reduced need for dust suppression; in terms of equipment maintenance, the wear rate of the loader's front fender decreased by approximately 42% due to a significant reduction in flying rocks. Considering both direct and indirect costs, the overall cost per cycle decreased by approximately 12% to 14%, with a significantly expanded safety margin.

[0091] To facilitate rapid verification, key indicators are compared as shown in the table below (traditional methods use values ​​measured under the same geological conditions and cycle advance conditions at adjacent sections; the present invention uses comparison values ​​from the same team and with the same equipment):

[0092]

[0093] The examples above clearly demonstrate that by introducing a continuous, slow-release structure with reverse absorption and plastic blockage at the stepped boundary, organizing sequential avoidance and rhythmic advancement according to a rhythmic structural index, constraining backflow with reverse adsorption, and directional energy release through granular channels, the present invention achieves stable and measurable improvements in safety, quality controllability, energy utilization efficiency, and overall economy. These improvements stem from the suppression of backflow superposition after the energy propagation path is clearly shaped, the weakening of energy retention at the turning point, and the refined management of the release sequence, ultimately transforming tunneling from passively accepting blasting results into a controllable process of actively orchestrating energy behavior.

[0094] This invention measures the reflection intensity of each borehole individually and constructs the energy propagation trajectory and boundary reflection response spectrum to form a coupled parameter calibration chain. This chain is used to quantitatively configure the charge density, cavity spacing, and sealing hardness of each section. Furthermore, an early unloading zone is set up at the turnaround point, and a reverse impact absorption pad and a plastic elastic blocking ring are embedded along the stepped boundary. Finally, a rhythmic structural index is used as the timing reference, combined with a periodic detonation device, a reverse adsorption energy blocking structure, and a granular energy release channel working in synergy. This achieves dual control by spatially dispersing incident energy and temporally staggering energy peaks, eliminating energy stagnation and back-and-forth reversals in the middle section, preventing premature loosening or self-excitation of undetonated sections. This significantly reduces the peak vibration of the tunnel face, reduces over-excavation and under-excavation, compresses the flyrock dispersion range, reduces the charge consumption per unit advance, and shortens the post-blast accessibility time. Ultimately, this simultaneously improves tunneling and breaking efficiency, construction controllability, and on-site safety margins, and provides quantifiable feedback for closed-loop monitoring correction and engineering promotion.

[0095] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for bench staging of explosives for use in tunneling, characterized by, Comprise the following steps: S1, blasthole boundary reflection response spectrum drawing ①Before the blasting construction, according to the blasthole distribution map and geological exploration data determined by the excavation design, the rock mass structure, lithology type, medium density, elastic modulus and acoustic wave propagation characteristics of each blasthole along the depth direction are calibrated, and the parameter comparison table of blast speed, acoustic impedance, lithology and depth is established; ②According to the parameter comparison table, the directional detonation method is used for field test, the stress wave response measurement array is set along the length direction outside the blasthole, and the energy arrival time, amplitude intensity and waveform change of the explosion wave at different depth sections are recorded; ③According to the measurement results, the energy propagation trajectory diagram is constructed, the reflection, transmission and turning path of each section of explosion wave are marked, and the energy residence area and energy superposition area are determined; ④According to the energy propagation trajectory diagram, the reflection time, reflection amplitude, energy residence time and frequency information are extracted, and the blasthole boundary reflection response spectrum is drawn; S2, construction of coupling parameter scale chain According to the blasthole boundary reflection response spectrum diagram drawn in step S1, the energy reflection aggregation peak value appearing in the energy propagation trajectory is identified, the energy superposition position and energy turning point are extracted, the blasthole section depth information and rock mass medium parameters are combined to construct the coupling parameter scale chain; S3, construction of energy release and transmission time sequence avoidance window Using the coupling parameter scale chain constructed in step S2, the explosive density of each section of charge in each blasthole, the cavity spacing and the hardness parameters of the blocked area are quantitatively configured, and the pre-unloading area with energy release function is arranged at the energy turning point position to construct the energy release and transmission time sequence avoidance window; S4, rhythm type structure index generation Taking the time sequence avoidance window constructed in step S3 as the control core, reverse impact absorbing pad and plastic elastic blocking ring are arranged in the step boundary area of each blasthole, continuous slow-release structure with micro gap change function is formed by expanding the unloading area, and rhythm type structure index of guided energy backflow path is generated; S5, establishment of closed loop control energy balance system Based on the rhythm type structure index, the energy backflow path in the blasthole is dynamically adjusted, the periodic control initiation device, the reverse adsorption type energy blocking structure and the granulation energy release channel are cooperatively operated, the explosion energy is smoothly guided out along the energy release channel, and the closed loop control energy balance system is established.

2. A method for benching of explosives for tunneling according to claim 1, characterized in that, Most of the coupling parameter scale chain construction steps in step S2 are as follows: ①Select the reflection wave section with reflection intensity greater than 40% of the initial energy amplitude of explosion as the key analysis area, identify the energy reflection aggregation peak value and determine the energy superposition position; ②According to the space position of energy turning point, reflection amplification percentage, residence time and propagation path time sequence of energy propagation trajectory, the energy turning characteristics are obtained; ③Combined with the depth position of blasting charge and the medium parameters of rock mass, the three parameter cross table of reflection intensity, charge density and medium impedance is constructed to form the coupling parameter scale chain for charge adjustment; ④According to the coupling parameter scale chain, the charge structure adjustment interval, adjustment item and adjustment amplitude of each blasthole are calibrated to determine the charge performance requirements and medium coupling conditions.

3. A method of benching and filling explosive material for use in tunneling according to claim 2, wherein: When constructing the three-parameter cross table of reflection intensity, charge density and medium impedance, the detonation velocity gradient of the adjacent charge segments above and below the energy turning point is corresponded with the medium acoustic impedance jump rate to determine the turning point control area, and the charge density adjustment priority, cavity spacing restriction and elastic modulus of the blocking material are taken as the control parameters to form the precise adjustment benchmark for guiding the charge density and structural configuration.

4. A method for benching of explosives for tunneling according to claim 1, characterized in that, The S3 step is a time sequence avoidance window generation step of energy release and transmission, and the generation steps are as follows: ①According to the coupling parameter scale chain, the charge density, cavity spacing and hardness of the blocking area of each blast hole along the depth direction are quantitatively configured, and the energy turning point section is taken as the key configuration object; ②A double-layer sealing zone is set in the key section, the inner layer is an elastic energy-absorbing mineral fiber, and the outer layer is a silica powder-containing colloidal material, the sealing thickness and bonding strength are determined according to the scale chain, and the energy-absorbing foam structure is configured in the non-key section to limit the hardness parameter; ③Radial buffer auxiliary holes are drilled at the energy turning point position, and fast-decay detonation explosives are filled into the auxiliary holes, a low-density cavity belt and an anti-explosion rubber layer are arranged around the auxiliary holes to construct an advance unloading area with directional energy release and guided release functions; ④The energy-absorbing structure transition zone is expanded outward along the adjacent segments above and below the advance unloading area, and radial unloading small holes are drilled in the surrounding rock to form a continuous time sequence avoidance window.

5. A method of benching explosive charges for use in tunneling according to claim 4 wherein: The radial buffer auxiliary holes in the advance unloading area are provided with an anti-explosion rubber layer between the main holes, the outer periphery of the auxiliary holes is filled with a low-density cavity belt and connected to an external energy release shaft, and a strong air permeability quartz sand filter layer is laid on the upper part of the auxiliary holes to form a composite unloading structure with energy release guiding and compressed echo delay functions.

6. A method of bench staging of explosives for use in tunneling according to claim 5 wherein The S4 step is a rhythm type structure index generation step, and the generation steps are as follows: ①According to the spatial boundary of the time sequence avoidance window and the energy retention position, the arrangement position of the reverse impact absorbing pad is determined in the step boundary area, and the composite absorbing pad is installed along the hole wall to form a ring-shaped energy-absorbing structure; ②A plastic elastic blocking ring is installed in the area below the reverse impact absorbing pad, a controllable micro-gap release port is formed through a longitudinal shallow groove structure to realize the delay regulation of the energy transmission rhythm; ③A polyurethane foam blocking ring belt, a glass bead and rubber particle disturbance belt and a metal powder reflection turning belt are arranged in the upward and downward directions of the reverse impact absorbing pad and the plastic elastic blocking ring respectively to form a multi-layer slow-release structure; ④The response time, attenuation intensity and deformation displacement data of the absorbing pad, blocking ring and slow-release structure in the explosion process are recorded to establish a rhythm type structure index; ⑤According to the rhythm type structure index, the structure response time difference and amplitude reduction of different step boundary segments are verified and rhythm calibrated to form a rhythm distribution model.

7. A method of bench staging of explosives for use in tunneling according to claim 6 wherein: Based on the rhythm type structure index, the energy backflow path in the blast hole is dynamically adjusted; periodic control initiation devices, reverse adsorption energy blocking structures and granulated energy release channels are arranged, and the three are operated cooperatively to make the explosion energy smoothly guided out along the energy release channel.

8. A method of bench staging of explosives for use in tunneling according to claim 7 wherein A closed-loop energy balance is also constructed, and the closed-loop energy balance control steps are as follows: ①According to the response time and wave peak delay of the energy turning section in the rhythm type structure index, periodic control initiation devices are arranged at each rhythm node and the detonation time sequence accuracy and distribution are determined; ②In the short-range area downstream of each blasting node, a reverse adsorption energy blocking structure is arranged, which uses a three-layer composite blocking body to tightly adhere to the hole wall to adsorb the returning wave and reduce the reflection amplitude; ③Radial through energy dissipation channels are drilled from the end of the blast hole to the surrounding rock, which are filled with granular media in layers and equipped with breathing exhaust belts to guide out the residual energy; ④The response time parameters of the initiation device, blocking structure, and energy dissipation channel are linked with the rhythm type structure index, and time domain joint debugging is implemented to ensure the energy transmission sequence and peak value misalignment; ⑤According to the closed-loop verification results of the linkage operation monitoring, the initiation timing and blocking response parameters are adjusted through the feedback of field explosion observation data, and the energy balance closed loop is completed.

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