Construction method of high and steep slope grading horse path cooperated with slope cutting and load reduction and drainage system

Abstract

The present application relates to geotechnical engineering and geological disaster prevention technical field, specifically relates to a kind of high and steep slope grading horse path cooperative slope cutting load reduction and drainage system construction method, including the following steps: including from top to bottom gradually carried out slope cutting load reduction and drainage system construction, including the following steps: S100: based on the potential sliding surface of the high and steep slope to be governed determines slope cutting load reduction and grading horse path structure parameters, from top to bottom grading slope excavation is carried out, and the section of each horse path excavated is shaped into the counter-inclined surface inclined to mountain side;S200: water intercepting ditch is excavated on the counter-inclined surface of each horse path mountain side, and oblique drainage hole is drilled to mountain interior at the mountain side slope foot of the water intercepting ditch.The present application effectively consumes the kinetic energy of down-flow by constructing counter-inclined surface horse path inclined to mountain side and cooperating with inter-level vertical energy dissipation structure, and prevents slope scouring damage caused by height difference.

Description

Technical Field

[0001] This invention relates to the fields of geotechnical engineering and geological disaster prevention technology, specifically to a construction method for a graded ramp-assisted slope reduction and drainage system for steep slopes. Background Technology

[0002] In geotechnical engineering treatment and earthwork excavation of steep slopes, the construction of graded slope cutting and drainage systems is a conventional means to ensure slope stability. However, existing methods for constructing steep slopes suffer from a core problem: a severe disconnect between the slope cutting and unloading process and the internal water pressure release process. Specifically, traditional construction typically employs a linear process of cutting slopes from top to bottom at fixed depths, followed by the unified construction of surface intercepting ditches and underground drainage holes after the slope has been formed. This physically separated construction model leads to the following three levels of technical defects: First, traditional graded horse trails are mostly designed with horizontal planes or along the slope. Under rainfall conditions, surface runoff is very likely to converge and overflow in the horse trail area. At the same time, due to the large vertical drop between the high and steep slopes, the gravitational potential energy is quickly converted into high kinetic energy when the water flows down the slope. This can easily cause severe shear stress erosion and damage to the intercepting ditches and slopes of the lower horse trails, leading to local soil erosion and shallow landslides.

[0003] Secondly, steep slopes often contain complex underground pore water networks, and simple external slope cutting and load reduction can cause a severe redistribution of stress within the slope. Existing technology has failed to establish a direct spatial connection between the release channels of deep pore water pressure and the surface interception system, resulting in groundwater not being effectively drained before surface water collection, and water easily lingering and infiltrating at the base of the slope.

[0004] Third, current construction methods lack a process feedback mechanism based on real-time hydraulic responses within the slope. The cutting progress of excavation equipment relies entirely on static initial design drawings, failing to consider changes in deep pore water pressure within the excavated section as a prerequisite for subsequent slope-cutting actions. In actual engineering projects, when rainfall or unloading causes a sudden increase in internal pore water pressure and a significant decrease in the anti-sliding force of the potential sliding surface, if the excavation equipment continues cutting the lower soil according to the original plan, it is highly likely to exceed the slope's limit equilibrium state, thereby triggering a sudden traction landslide during the construction period. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a construction method for a graded ramp-assisted slope reduction and drainage system for steep slopes, comprising the following steps: including the construction of the slope reduction and drainage system in stages from top to bottom, comprising the following steps: S100: Based on the potential sliding surface of the steep slope to be treated, determine the slope reduction and load reduction amount and graded horse trail structural parameters, carry out graded slope cutting and excavation from top to bottom, and modify the cross-section of each graded horse trail to be tilted towards the mountain side. S200: Excavate intercepting ditches on the mountainside of the reverse slope of each level of the horse trail, and drill inclined drainage holes into the mountain at the foot of the slope on the mountainside of the intercepting ditches. Connect the outlet of the inclined drainage holes to the intercepting ditches to release the deep pore water pressure of the slope and drain water in conjunction with the intercepting ditches. S300: Excavate a vertical guide water channel between two adjacent levels of the horse trail, and set an energy dissipation structure in the vertical guide water channel. Connect the intercepting channel of the upper level horse trail to the vertical guide water channel through the rapid flow channel, so that the drainage from the upper level is dissipated and slowed down by the energy dissipation structure and then flows into the intercepting ditch of the lower level horse trail. S400: Monitoring components are installed in the inclined drainage hole and on the slope section to obtain real-time pore water pressure. When the real-time pore water pressure drops to a preset safety threshold, the slope cutting excavation of the next level slope is started to realize dynamic coordinated control of slope cutting and load reduction and water pressure release.

[0006] Further, in step S100, the graded catwalk structure parameters include the catwalk grade N and the anti-inclination angle. ,in The specific adjustment control conditions for modifying the cross-section of the excavated and formed horse trails at each level into a reverse slope inclined towards the mountain are as follows: the reverse slope angle α is kept between 3° and 5° so as to construct an in-situ water-blocking and water-conducting buffer zone between the slope levels.

[0007] Furthermore, the top-down graded slope cutting excavation is carried out using a stepped trenching excavation method, and the specific procedures include: The slope is divided into multiple excavation sections of preset width along the direction of the slope to be excavated. The excavated trench sections are sloped in a skip-ditch manner, with one trench excavated at a time. After the reverse slope of the current excavation section is repaired and the slope support strength of the section reaches 75% or more of the design requirements, the slope cutting excavation of the adjacent section shall be started.

[0008] Furthermore, the excavation of intercepting ditches on the mountainside of the reverse slope of each level of the horse trail specifically includes flexible protection construction of the intercepting ditches: A trench with a trapezoidal cross section is excavated on the mountain-facing side of the reverse slope. A composite geomembrane is fully laid on the bottom and outer walls of the trench to form an anti-seepage and anti-erosion layer; A permeable geotextile is laid on the inner slope of the ditch to allow shallow water to seep in and prevent soil erosion, thereby constructing the intercepting ditch with both seepage prevention and water permeability functions.

[0009] Furthermore, the drilling of inclined drainage holes into the mountainside and connecting their outlets to the intercepting ditch specifically includes: The drilling angle of the inclined drainage hole is controlled between 5° and 10°; After drilling, a PVC water pipe with permeable holes is inserted into the inclined drainage hole, and a filter screen is wrapped around the outer wall of the PVC water pipe to filter deep pore water and prevent silt blockage. Extend the outlet end of the PVC water pipe outward from the hole, and let it suspend or overlap into the intercepting ditch to form a direct discharge channel that connects the deep groundwater of the slope to the surface drainage network of the horse trail.

[0010] Furthermore, the provision of an energy dissipation structure within the vertical guide channel specifically involves constructing a rigid energy dissipation sill within the vertical guide channel: On the inner bottom surface of the vertical guide channel, a concrete energy dissipation block with a "W" shaped cross section is cast in place at intervals of 1.5m to 2.0m along the direction of water flow. The protrusions of the "W"-shaped concrete energy dissipation block face the direction of water flow in, so as to divert the downstream water flow laterally and guide it to the two side walls of the vertical guide channel for mutual collision and energy dissipation, thereby disrupting the continuity of water flow.

[0011] Furthermore, the provision of an energy dissipation structure within the vertical guide channel specifically involves laying a flexible energy dissipation strip within the vertical guide channel. A stepped permeable buffer pad made of lead wire gabions is integrally anchored and laid inside the vertical guide channel. The stepped permeable buffer pad includes multiple gabion steps stacked longitudinally along the vertical guide channel. The height difference between the gabion steps is used for gravity energy dissipation, and the water-resistant friction of the pores of the stones inside the gabion is used for seepage energy dissipation.

[0012] Furthermore, the step of deploying monitoring components within the inclined drainage hole and on the sloped cross-section to obtain real-time pore water pressure specifically includes constructing a three-dimensional sensor network combining shallow and deep sensors: Deep pore water pressure gauges are installed at the deep end and middle of each of the inclined drainage holes to monitor the dynamic changes of deep groundwater pressure at the core sliding surface inside the slope. Shallow water pressure sensors are installed in the shallow soil of the reverse slope and the cut slope section of the horse trail at each level to monitor the changes in shallow seepage water pressure caused by rainfall infiltration. Flow meters are installed at the intersection of the intercepting ditches and vertical guide channels at each level to monitor the surface drainage velocity and instantaneous flow rate in real time. This, together with the deep pore water pressure gauge and the shallow water pressure sensor, forms a monitoring component for linkage monitoring.

[0013] Furthermore, when the real-time pore water pressure drops to a preset safety threshold, the next level of slope excavation is initiated to achieve dynamic coordinated control of slope reduction and water pressure release. This specifically includes process interruption and dynamic supplementation control logic based on data feedback. The safety threshold is set as the maximum anti-sliding pore water pressure value allowed on the potential sliding surface of the current excavated slope under the limit equilibrium state.

[0014] Furthermore, when the real-time pore water pressure collected by the deep pore water pressure gauge is greater than the safety threshold, and the discharge flow monitored by the flow meter shows a stagnant or decreasing trend, the construction circuit breaker mechanism is triggered to forcibly suspend the slope cutting and excavation operation of the next level slope. During the construction shutdown period, the current excavation level of the walkway is kept in its in-situ unloading state. The drainage holes between the existing inclined drainage holes are dynamically supplemented and reinforced by halving the spacing. The construction shutdown is lifted and the excavation of the next level of slope is started only when the value collected by the deep pore water pressure gauge is continuously lower than the safety threshold and the stability time reaches more than 48 hours.

[0015] Beneficial effects This invention constructs a reverse-sloping ramp that tilts towards the mountainside and incorporates vertical energy dissipation structures between stages. By utilizing mechanical impact and porous media friction mechanisms, it effectively dissipates the kinetic energy of the flowing water, preventing slope erosion caused by elevation differences. Simultaneously, the physical channels of deep, inclined drainage holes are directly integrated into surface intercepting ditches, establishing a drainage network that links deep and shallow pore water. Furthermore, it creatively introduces a process-based melting and supplementary feedback algorithm based on real-time pore water pressure thresholds. This creates a tight dynamic collaborative closed loop between the unloading and advance of earthmoving machinery and the rate of water pressure release within the slope, significantly reducing the risk of landslides caused by stress and water pressure imbalances during construction on steep slopes and improving the overall safety control precision of the project. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the construction process of the collaborative slope reduction and dynamic closed-loop control of the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but includes other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] The present invention will now be described in further detail with reference to the accompanying drawings: Example: like Figure 1 As shown, a construction method for a graded ramp-assisted slope reduction and drainage system for steep slopes includes the following steps: The system is constructed in stages from top to bottom. S100: Based on the potential sliding surface of the steep slope to be treated, determine the slope reduction and load reduction amount and graded horse trail structural parameters, carry out graded slope cutting and excavation from top to bottom, and modify the cross-section of each graded horse trail to be tilted towards the mountain side. S200: Excavate intercepting ditches on the mountainside of the reverse slope of each level of horse trail, and drill inclined drainage holes into the mountain at the foot of the slope on the mountainside of the intercepting ditches. Connect the outlet of the inclined drainage holes to the intercepting ditches to release the deep pore water pressure of the slope and drain water in conjunction with the intercepting ditches. S300: Excavate a vertical guide channel between two adjacent horse trails, and set up an energy dissipation structure in the vertical guide channel. Connect the intercepting channel of the upper horse trail to the vertical guide channel through the rapid flow channel, so that the drainage from the upper level is decelerated and discharged into the intercepting ditch of the lower horse trail after being de-energized by the energy dissipation structure. S400: Monitoring components are installed in the inclined drainage holes and on the slope section to obtain real-time pore water pressure. When the real-time pore water pressure drops to the preset safety threshold, the slope excavation of the next level slope is started to achieve dynamic coordinated control of slope reduction and water pressure release.

[0020] Furthermore, the specific implementation process of step S100 is as follows: I. Determination of slope parameters and division of excavation sections: Topographic and geomorphological mapping data, as well as the physical and mechanical parameters of the soil and rock mass, were obtained for the steep slope to be treated. The acquired geological mapping data was imported into finite element analysis software for geotechnical engineering. The initial safety factor of the steep slope under natural conditions and a set rainfall scenario was calculated using the strength reduction method, and the spatial three-dimensional coordinates of the potential sliding surface were extracted. Based on the spatial coordinates of the potential sliding surface and the set target safety factor, the volume of soil and rock to be stripped from the sliding body was calculated using the limit equilibrium method, thereby determining the overall slope reduction and load reduction amount.

[0021] Based on the overall slope reduction and load reduction, and the original absolute elevation difference of the steep slope to be treated, the graded walkway structure parameters are determined from top to bottom. The graded walkway structure parameters specifically include the walkway level N and the walkway inclination angle α. Based on elevation data, the walkway level N is set to ≥ 2, with one level of walkway set every 8m to 12m of vertical drop. After determining the overall parameters, the slope plane at the current working elevation is divided into several continuously distributed excavation sections along the direction of the slope to be excavated. The transverse excavation width of a single excavation section is set to 10m to 15m. The specific value of the excavation width is set based on the measured rock mass quality index (RQD) and the calculated rock mass self-stabilization time. The multiple excavation sections are numbered alternately using odd and even numbers.

[0022] II. Implementation of stepped slope cutting with alternating excavations: Following a skip-the-left-excavation sequence, mechanical earthmoving operations are initiated first for odd-numbered excavation sections. While the soil is being cut downwards in the odd-numbered excavation sections, the soil in the adjacent even-numbered excavation sections is left intact, serving as temporary support to bear the lateral earth pressure from both sides. The excavation equipment is then used to continuously cut the slope of the odd-numbered excavation sections until the bottom elevation reaches the design reference elevation for the current level of the walkway.

[0023] III. Trimming, shaping, and compaction of the reverse slope of the catwalk: Once the bottom elevation of the current excavated section reaches the design benchmark elevation, immediately initiate the reverse slope trimming operation of the cross section of the walkway. Operate a grader or excavating equipment equipped with a tilting bucket, along with a total station or 3D laser scanner for dynamic elevation tracking measurement. Through mechanical cutting and filling actions, trim the slope of the newly formed walkway surface towards the interior of the mountain, creating a reverse slope surface.

[0024] During the trimming process, the inclination angle α of the reverse slope is strictly controlled between 3° and 5° using measuring instruments. After trimming, a road roller is deployed to compact the formed reverse slope. The number of compaction passes is set to 4 to 6, and soil density is tested after compaction to ensure that the in-situ compaction degree of the reverse slope reaches 93% or higher, providing a flat and load-bearing capacity-compliant construction base for subsequent processes.

[0025] IV. Coordinated activation of newly exposed slope support and adjacent trench sections: After the reverse slope of the currently odd-numbered excavation section has been trimmed and compacted, anchor-sprayed support operations are simultaneously carried out on the newly excavated exposed cutting slope and the toe of the ramp. A down-the-hole drill is used to drill holes on the cutting slope at a preset spacing, inserting full-length bonded anchor bolts and grouting them in place. Subsequently, a steel mesh is laid and anchored on the cutting slope, and a 10cm to 15cm thick early-strength concrete surface layer is sprayed onto the steel mesh and the slope using a wet-spraying process.

[0026] After the shotcrete surface layer has set, early compressive strength data of the shotcrete is obtained in real time at the construction site using a concrete rebound hammer or in-situ core sampling compressive strength test. The real-time compressive strength data is compared with the set design strength value. When the test data shows that the compressive strength of the slope support surface layer of the current excavation segment reaches 75% or more of the design strength value, it is determined that the stress redistribution of the current segment has met the stability condition. After the above condition is met, the excavation restrictions on adjacent even-numbered excavation segments are lifted, and the slope reduction and load reduction excavation of the even-numbered excavation segments is started, strictly repeating the aforementioned steps of elevation cutting, reverse slope trimming, compaction, and anchor shotcrete support. This process is carried out alternately until all excavation segments of the current slope are completely connected laterally, forming a complete walkway system with a continuous lateral reverse slope.

[0027] Furthermore, the specific implementation process of step S200 is as follows: After the reverse slope of the graded walkway is trimmed and compacted, an excavation baseline is laid out along the longitudinal boundary line on the mountainside of the reverse slope. A small tracked excavator is deployed to excavate trenches along the baseline, cutting the soil to form trapezoidal trenches. The bottom width of the trapezoidal trench is controlled between 0.5m and 0.8m, and the excavation depth is controlled between 0.6m and 1.0m. The slope ratio of both sides of the trench is adjusted to 1:1 to 1:1.5. After the trapezoidal trench is formed, a walk-behind rammer is used to compact the soil at the bottom and on both inner walls of the trench, requiring the soil at the trench base to reach a compaction degree of 90% or higher. Sharp stones or plant roots attached to the surface are removed to provide a smooth working surface for paving.

[0028] The composite geomembrane and permeable geotextile are laid inside the leveled trapezoidal trench. The composite geomembrane is unfolded longitudinally along the trench, adhering tightly to the bottom plane of the trench and the outer wall away from the mountainside for full coverage. The overlapping edges of the composite geomembrane are sealed using a hot-melt welding process, and the top edge of the composite geomembrane is anchored into the soil at the top of the outer trench wall using U-shaped steel nails.

[0029] A permeable geotextile is laid on the inner wall of the trapezoidal trench, near the mountainside. The permeable geotextile is laid tightly against the soil of the inner trench wall, with its bottom edge extending downwards and covering the underlying composite geomembrane, ensuring an overlap width of at least 15cm. Polyurethane adhesive is used to fix the overlap joints, and U-shaped steel nails are used to anchor the top edge of the permeable geotextile into the slope at the top of the inner trench wall, forming a composite flexible protective structure that is seepage-proof on the outer side and bottom, and permeable on the inner side near the mountainside.

[0030] Set the borehole position 10cm to 20cm above the boundary line of the slope toe on the mountainside of the trapezoidal cross-section trench. Position the fully hydraulic horizontal drilling rig, align the drill rod with the borehole position, and adjust the tilt angle of the drilling rig column and drill rod guide rail to keep the drill bit elevation angle within the range of 5° to 10°. Start the drilling rig and perform rotary drilling into the mountain. During drilling, use clean water to flush and remove slag. Control the hole diameter between 100mm and 110mm, and the drilling depth must penetrate the potential sliding surface calculated by the finite element software and penetrate at least 2.0m into the mountain.

[0031] During the drilling operation, the internal water guiding components are assembled simultaneously. A PVC pipe with an outer diameter of 75mm is cut, and holes are drilled in a staggered, quincunx pattern on the pipe wall using a mechanical drill bit. The diameter of the water-permeable holes is set to 8mm to 10mm, and the opening rate of the water-permeable holes is controlled between 15% and 20%. Two layers of non-woven fabric filter mesh are tightly wrapped around the outer wall of the drilled PVC pipe, and nylon cable ties are used to secure it circumferentially every 30cm along the longitudinal direction of the PVC pipe, thus creating a PVC water guiding pipe with a filter mesh.

[0032] After cleaning the inclined borehole, the assembled PVC water pipe with filter screen is pushed into the mountainside along the borehole. During the pushing operation, a section of the PVC water pipe near the external opening is retained as the outlet. The outlet is controlled to extend outward from the borehole, so that the outlet directly passes through the permeable geotextile and extends suspended above the internal space of the trapezoidal cross-section trench, or the bottom of the outlet is placed directly on the composite geomembrane at the bottom of the trapezoidal cross-section trench.

[0033] After fixing the outlet position, inject water-swellable polyurethane sealant or fill with quick-setting cement mortar into the annular gap between the outer wall of the PVC water pipe and the soil at the borehole opening. The filling depth should be no less than 30cm to completely seal the annular gap at the borehole opening and cut off the physical path of surface water flowing back into the slope along the borehole opening.

[0034] Furthermore, the specific implementation process of step S300 is as follows: Between adjacent upper and lower level walkways, a longitudinal excavation outline is laid out along the direction of the maximum slope line. Excavation equipment is deployed to cut the surface soil and rock along the longitudinal excavation outline, forming a rectangular vertical guide channel. The bottom width of the rectangular vertical guide channel is controlled to be 0.8m to 1.2m, and the excavation depth is controlled to be 0.6m to 1.0m.

[0035] At the junction of the intercepting ditch on the inner side of the upper-level walkway and the top of the vertical guide channel, a rapid flow channel with an inclination angle greater than 30° is excavated to smoothly transition the bottom surface of the intercepting ditch to the bottom surface of the vertical guide channel. After the vertical guide channel and the rapid flow channel are excavated and shaped, the bottom of the channel and the side walls are manually cleaned and mechanically compacted. A 5cm to 10cm thick layer of C15 plain concrete is then laid on the bottom and wall surfaces to provide a hard and flat internal structural base.

[0036] After the plain concrete leveling layer reaches its initial setting strength, elevation measurements and spacing are conducted along the longitudinal centerline on the inner bottom surface of the vertical guide channel. Irregularly shaped wooden formwork is alternately erected inside the vertical guide channel at longitudinal intervals of 1.5m to 2.0m. A steel reinforcement cage, connected to the pre-embedded steel bars on the bottom surface, is tied inside the irregularly shaped wooden formwork. Subsequently, C30 grade fine aggregate concrete is poured to form a concrete energy dissipation block with a "W" shaped cross-section.

[0037] The height of the "W"-shaped concrete energy dissipation block is controlled to be between 0.4m and 0.6m, ensuring its width perfectly matches the bottom width of the vertical guide channel. The central geometrically protruding end of the "W"-shaped concrete energy dissipation block is precisely oriented so that it faces the direction of the downward flow of water. When the water collected from above flows down the vertical guide channel, the front end of the water body physically impacts the central protruding end of the "W"-shaped concrete energy dissipation block. The direction of the water flow is forced to deflect laterally due to the physical obstruction, and it then impacts the left and right walls of the vertical guide channel, resulting in secondary impacts. Through the mechanical action of physical obstruction and forced water flow reversal, the continuous gravitational acceleration of the downward flow is interrupted.

[0038] As another physical implementation of energy dissipation structures, a flexible energy dissipation strip composed of porous media is laid above the plain concrete leveling layer of the vertical guide channel. Highly corrosion-resistant hot-dip galvanized steel wire mesh is pre-cut on-site and assembled into rectangular gabion boxes with dimensions of 1.0m long, 0.5m wide, and 0.5m high. The rectangular gabion boxes are then filled with hard, unweathered boulders with a particle size between 10cm and 20cm, controlling the porosity of the boulders to be between 25% and 30%. The boxes are then sealed and tied to form closed gabion units.

[0039] The filled gabion units are transported into the vertical guide channel and stacked longitudinally from bottom to top. A height difference of 0.2m to 0.3m is set between adjacent gabion units to form multiple longitudinally distributed gabion steps. 1.0m long threaded steel anchors are driven through the mesh of the gabion units and into the soil and rock at the bottom of the vertical guide channel to lock the spatial position of the gabion steps. The flowing water over the surface of the gabion steps creates a cascading potential energy dissipation. Simultaneously, some water is forced into the pores formed by the stacked stones under the pressure of the water head, utilizing the physical frictional resistance between the water flow and the rough stone surface to dissipate the kinetic energy of the water.

[0040] At the outlet of the vertical guide channel, cut the reverse slope of the next-level walkway and the outer wall of the intercepting ditch to construct a connecting T-junction. Align the bottom elevation of the vertical guide channel outlet with the highest design water level of the next-level walkway intercepting ditch. At the junction of the T-junction, apply polysulfide sealant or lay a double-layer composite waterproof membrane to seal all possible micro-cracks that could leak into the soil, ensuring that the energy-dissipating and slowed water flows seamlessly into the next-level walkway intercepting ditch, completing the fully enclosed and interconnected drainage of surface water between levels.

[0041] Furthermore, the specific implementation process of step S400 is as follows: After the PVC water pipe with filter screen is installed and fixed, vibrating wire deep pore water pressure gauges are inserted into the core sliding surface of the mountain and the middle area of ​​the PVC water pipe along its internal channel. Shallow test holes are drilled into the soil at a depth of 0.5m to 1.0m below the surface of the slope and on the reverse slope surface. Resistance strain gauge shallow water pressure sensors are embedded inside these shallow test holes, and the holes are sealed with bentonite slurry after installation. Ultrasonic flow meters are fixed to the inner wall of the T-junction node between the trapezoidal trench and the vertical guide channel using expansion bolts. The data transmission cables of the vibrating wire deep pore water pressure gauge, the resistance strain gauge shallow water pressure sensor, and the ultrasonic flow meter are led out and connected to a waterproof data acquisition box pre-fixed on the outer edge of the walkway, establishing a three-dimensional physical sensing network covering deep water pressure, shallow water pressure, and surface runoff flow.

[0042] The microprocessor inside the data acquisition box receives manually input initial safety thresholds. The specific value of the initial safety threshold is the maximum allowable deep pore water pressure value for maintaining the potential sliding surface stability coefficient greater than 1.20 under the current excavation level slope condition, under limit equilibrium analysis. The microprocessor in the data acquisition box reads the voltage signals from the vibrating wire deep pore water pressure gauge and the resistance strain gauge shallow water pressure sensor via data transmission cables at a sampling frequency of once per minute, converting them into water pressure values. Simultaneously, it reads the flow velocity and instantaneous flow rate values ​​from the ultrasonic flow meter and writes all collected values ​​into an external storage module.

[0043] A closed-loop decision algorithm is pre-programmed into the microprocessor of the data acquisition box. When the real-time pore water pressure value collected by the vibrating wire deep pore water pressure gauge exceeds the initial safety threshold for three consecutive sampling cycles, and the instantaneous flow rate value of the synchronously read ultrasonic flow meter shows a continuous decrease or stagnation to zero, the microprocessor sends a shutdown signal to the external construction control terminal via the wireless communication module. Upon receiving the shutdown signal, the external construction control terminal forcibly disconnects the control loop of the next-level slope excavation equipment, stopping the physical cutting and unloading operation of the next-level slope soil.

[0044] With the slope cutting and unloading operations stopped, maintain the current spatial morphology and soil stress state of the excavated walkway unchanged. At the center point of two adjacent existing inclined drainage holes, drill additional drainage holes according to the drilling angle and diameter parameters defined in step S200. Insert identical PVC water pipes with filters into the additional drainage holes, reducing the lateral physical spacing of the inclined drainage holes to half of the original design spacing, thus forcibly expanding the cross-sectional area of ​​the physical channel for groundwater discharge from the slope into the intercepting ditch.

[0045] After the drainage holes are added and assembled, maintain the high-frequency sampling state of the data acquisition box once per minute. Continuously read the real-time pore water pressure value fed back by the vibrating wire deep pore water pressure gauge. When the real-time pore water pressure value steadily decreases below the initial safety threshold, and the real-time pore water pressure value remains below the initial safety threshold for a continuous period of 48 hours or more, the microprocessor sends a resumption signal to the external construction control terminal.

[0046] After receiving the resumption signal, the external construction control terminal restores the power supply to the lower-level slope excavation equipment and initiates the physical steps of elevation cutting and reverse slope trimming for the next level of slope. The aforementioned data collection, comparison, work stoppage supplementation, and resumption operations are executed in a cyclical manner from top to bottom along the ramp level until the elevation of the main drainage ditch at the slope toe is reached.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A construction method for a graded ramp-assisted slope reduction and drainage system for steep slopes, comprising the construction of a slope reduction and drainage system carried out step-by-step from top to bottom, characterized in that... Includes the following steps: S100: Based on the potential sliding surface of the steep slope to be treated, determine the slope reduction and load reduction amount and graded horse trail structural parameters, carry out graded slope cutting and excavation from top to bottom, and modify the cross-section of each graded horse trail to be tilted towards the mountain side. S200: Excavate intercepting ditches on the mountainside of the reverse slope of each level of the horse trail, and drill inclined drainage holes into the mountain at the foot of the slope on the mountainside of the intercepting ditches. Connect the outlet of the inclined drainage holes to the intercepting ditches to release the deep pore water pressure of the slope and drain water in conjunction with the intercepting ditches. S300: Excavate a vertical guide water channel between two adjacent levels of the horse trail, and set an energy dissipation structure in the vertical guide water channel. Connect the intercepting channel of the upper level horse trail to the vertical guide water channel through the rapid flow channel, so that the drainage from the upper level is dissipated and slowed down by the energy dissipation structure and then flows into the intercepting ditch of the lower level horse trail. S400: Monitoring components are installed in the inclined drainage hole and on the slope section to obtain real-time pore water pressure. When the real-time pore water pressure drops to a preset safety threshold, the slope cutting excavation of the next level slope is started to realize dynamic coordinated control of slope cutting and load reduction and water pressure release.

2. The construction method of a graded ramp-assisted slope cutting, load reduction, and drainage system for steep slopes according to claim 1, characterized in that, In step S100, the graded catwalk structure parameters include the catwalk grade N and the anti-inclination angle. ,in The specific adjustment control conditions for modifying the cross-section of the excavated and formed horse trails at each level into a reverse slope inclined towards the mountain are as follows: the reverse slope angle α is kept between 3° and 5° so as to construct an in-situ water-blocking and water-conducting buffer zone between the slope levels.

3. The construction method of a graded horse trail combined with slope cutting, load reduction and drainage system for steep slopes according to claim 2, characterized in that, The top-down graded slope cutting excavation is carried out using a stepped trenching excavation method, and the specific procedures include: The slope is divided into multiple excavation sections of preset width along the direction of the slope to be excavated. The excavated trench sections are cut in a skip-and-excavate manner. After the reverse slope of the current excavation section is repaired and the slope support strength of the section reaches 75% or more of the design requirements, the slope cutting excavation of the adjacent section shall be started.

4. The construction method of a graded ramp-assisted slope cutting, load reduction, and drainage system for steep slopes according to claim 3, characterized in that, The excavation of intercepting ditches on the mountainside of the reverse slope of the various levels of horse trails specifically includes the construction of flexible protection measures for the intercepting ditches: A trench with a trapezoidal cross section is excavated on the mountain-facing side of the anti-sloping surface; A composite geomembrane is fully laid on the bottom and outer walls of the trench to form an anti-seepage and anti-erosion layer; A permeable geotextile is laid on the inner slope of the ditch to allow shallow water to seep in and prevent soil erosion, thereby constructing the intercepting ditch with both seepage prevention and water permeability functions.

5. The construction method for a graded ramp-assisted slope cutting, load reduction, and drainage system for steep slopes according to claim 4, characterized in that, The drilling of inclined drainage holes into the mountainside and connecting their outlets to the intercepting ditch specifically includes: The drilling angle of the inclined drainage hole is controlled between 5° and 10°; After drilling, a PVC water pipe with permeable holes is inserted into the inclined drainage hole, and a filter screen is wrapped around the outer wall of the PVC water pipe to filter deep pore water and prevent silt blockage. Extend the outlet end of the PVC water pipe outward from the hole, and let it suspend or overlap into the intercepting ditch to form a direct discharge channel that connects the deep groundwater of the slope to the surface drainage network of the horse trail.

6. The construction method for a graded ramp-assisted slope cutting, load reduction, and drainage system for steep slopes according to claim 5, characterized in that, The energy dissipation structure is installed in the vertical guide channel, specifically by constructing a rigid energy dissipation sill in the vertical guide channel: On the inner bottom surface of the vertical guide channel, a concrete energy dissipation block with a "W" shaped cross section is cast in place at intervals of 1.5m to 2.0m along the direction of water flow. The protrusions of the "W"-shaped concrete energy dissipation block face the direction of water flow in, so as to divert the downstream water flow laterally and guide it to the two side walls of the vertical guide channel for mutual collision and energy dissipation, thereby disrupting the continuity of water flow.

7. The construction method for a graded ramp-assisted slope cutting, load reduction, and drainage system for steep slopes according to claim 6, characterized in that, The energy dissipation structure is installed in the vertical guide channel, specifically by laying a flexible energy dissipation strip in the vertical guide channel: A stepped permeable buffer pad made of lead wire gabions is integrally anchored and laid inside the vertical guide channel. The stepped permeable buffer pad includes multiple gabion steps stacked longitudinally along the vertical guide channel. The height difference between the gabion steps is used for gravity energy dissipation, and the water-resistant friction of the pores of the stones inside the gabion is used for seepage energy dissipation.

8. The construction method for a graded ramp-assisted slope cutting, load reduction, and drainage system for steep slopes according to claim 7, characterized in that, The method of deploying monitoring components within the inclined drainage holes and on the sloped cross-section to obtain real-time pore water pressure specifically includes constructing a three-dimensional sensor network combining shallow and deep sensors: Deep pore water pressure gauges are installed at the deep end and middle of each of the inclined drainage holes to monitor the dynamic changes of deep groundwater pressure at the core sliding surface inside the slope. Shallow water pressure sensors are installed in the shallow soil of the reverse slope and the cut slope section of the horse trail at each level to monitor the changes in shallow seepage water pressure caused by rainfall infiltration. Flow meters are installed at the intersection of the intercepting ditches and vertical guide channels at each level to monitor the surface drainage velocity and instantaneous flow rate in real time. This, together with the deep pore water pressure gauge and the shallow water pressure sensor, forms a monitoring component for linkage monitoring.

9. A construction method for a graded ramp-assisted slope cutting, load reduction, and drainage system for steep slopes according to claim 8, characterized in that, When the real-time pore water pressure drops to a preset safety threshold, the next level of slope excavation is initiated, achieving dynamic coordinated control of slope reduction and water pressure release. Specifically, this includes process interruption and dynamic supplementation control logic based on data feedback. The safety threshold is set as the maximum anti-sliding pore water pressure value allowed on the potential sliding surface of the current excavated slope under the limit equilibrium state.

10. A construction method for a graded ramp-assisted slope cutting, load reduction, and drainage system for steep slopes according to claim 9, characterized in that, When the real-time pore water pressure collected by the deep pore water pressure gauge is greater than the safety threshold, and the discharge flow monitored by the flow meter shows a stagnant or decreasing trend, the construction circuit breaker mechanism is triggered, forcibly suspending the slope cutting and excavation operation of the next level slope. During the construction shutdown period, the current excavation level of the walkway is kept in its in-situ unloading state. The drainage holes between the existing inclined drainage holes are dynamically supplemented and reinforced by halving the spacing. The construction shutdown is lifted and the excavation of the next level of slope is started only when the value collected by the deep pore water pressure gauge is continuously lower than the safety threshold and the stability time reaches more than 48 hours.

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