Methods for constructing firewood rafts on ice in dangerous river sections

Abstract

This invention discloses a method for constructing raft toe protection on ice in dangerous river sections, belonging to the field of ice construction technology for water conservancy projects. This method addresses the technical problems of uncontrollable sinking trajectory, easy twisting and damage of the raft body, and poor positioning accuracy in traditional raft toe protection construction on ice. The key to its solution lies in: excavating multiple guide grooves and ice ridges with melting-promoting holes on the ice surface to form a construction benchmark; controlling the melting process by injecting a melting-promoting agent with a thickness gradient into different grooves, allowing the raft unit to sink in stages along a predetermined path under the action of counterweight; firstly, the ice ridge area melts preferentially to release the raft body connection, and then the groove area melts differentially to generate a guiding effect, guiding the raft body to a stable and precise position. This method is mainly used to solve the problem of difficult construction of raft toe protection projects in cold regions during the freezing period, enabling precise and controllable laying of raft toe protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ice construction of hydraulic engineering. More particularly, the present application relates to a method for ice construction of river dangerous work with timber row protection. BACKGROUND

[0002] River dangerous work is a key node in the flood control engineering system, and the stability of its protection directly relates to the safety of the embankment. In the cold northern region, the river has a relatively long freezing period every year, which provides a unique operation window for using the ice surface as a construction platform for protection construction. The traditional timber row protection construction mostly chooses to be carried out in the dry season or by water operation with a ship, which has problems such as short construction period, great influence of water flow, and difficult positioning. The ice construction method can theoretically overcome these limitations and provide a longer effective construction period and more stable operation conditions for the treatment of river dangerous work.

[0003] The current common ice sinking row construction method is to directly assemble the timber row into shape on the ice surface after the ice layer reaches sufficient bearing strength, and then make the row sink into the riverbed by natural melting or artificial ice breaking. Although the bearing advantage of the ice surface is utilized, it still has many serious defects in practical application. First, the sinking process of the row body completely depends on the randomness of the ice layer melting, resulting in uncontrollable sinking trajectory. The slight differences in the contact state of each part of the row body with the ice layer, the degree of solar radiation, the water temperature distribution and other factors will cause the melting to be out of sync, which easily causes the row body to twist, fold or even tear during the descending process, seriously affecting the continuity of the protection effect.

[0004] Secondly, the existing technology lacks an effective sinking guide mechanism. Once the timber row is separated from the ice layer, it will freely fall under the action of gravity, and will often produce horizontal displacement and attitude deflection during the falling process due to the influence of factors such as water flow impact and riverbed slope, resulting in a large deviation between the final in-place position and the design position, especially in steep dangerous work sections, which often causes protection blanking at the slope foot and forms new safety hazards. In addition, the large timber row has uneven internal stress distribution during the sinking process, which easily causes structural damage and reduces the service life of the project.

[0005] In terms of melting control, the existing technology mostly uses the method of uniformly spreading melting agent or simply digging ice channels, which cannot achieve precise control of the melting process. Either the row body sinks as a whole and loses control, or the row body is partially suspended and deformed due to uneven melting. Especially for dangerous work sections that need to be accurately covered, the disordered sinking method cannot meet the engineering precision requirements. The existing technology has always failed to effectively solve the three core problems in ice sinking row construction: how to ensure that the timber row sinks according to the designed trajectory, how to maintain the structural integrity of the row body during the sinking process, and how to achieve precise positioning of the timber row on the slope surface.

[0006] Therefore, there is an urgent need for an ice construction method that can achieve precise control of the sinking process of the log raft, ensure the integrity of the log raft structure, and finally accurately position the log raft, so as to improve the construction quality and reliability of the river dangerous work toe protection project. SUMMARY

[0007] An object of the present application is to solve at least the above problems and provide at least the advantages to be described later.

[0008] Another object of the present application is to provide an ice construction method for river dangerous work log raft toe protection, which realizes precise and controllable sinking of log raft units along a predetermined trajectory by setting ice surface guide grooves and a differential melting system, effectively solves the technical problems of easy distortion and inaccurate positioning of the log raft in traditional ice construction, and significantly improves the construction quality and reliability of the toe protection project.

[0009] In order to achieve these objects and other advantages according to the present application, an ice construction method for river dangerous work log raft toe protection is provided, comprising:

[0010] S1. On the frozen river ice surface, a plurality of ice surface guide grooves extending along the river direction are chiseled at intervals along the design laying position of the log raft, ice ridges are formed between adjacent ice surface guide grooves, a plurality of melting holes are provided on the ice ridges, and melting agents are injected into the melting holes and the guide grooves;

[0011] S2. A plurality of log raft units adapted to the ice surface guide grooves are prepared and laid, each log raft unit comprising a middle main part sinking into the ice surface guide groove and a side part covering the surface of the ice ridge on both sides;

[0012] S3. On the ice ridge, the overlapping parts of adjacent log raft units are flexibly connected, so that all the log raft units are connected as a whole above the ice surface;

[0013] S4. A counterweight is applied to the middle main part of the log raft unit in the ice surface groove; when the ice layer melts, each log raft unit slides and sinks to the designed laying position along the path defined by the ice surface guide groove under the action of the counterweight;

[0014] Wherein, the thickness of the melting agent in the ice surface guide groove increases in turn along the extension direction of the embankment to the river, so that the two side parts of adjacent log raft units overlap up and down.

[0015] Preferably, the ice surface guide groove is injected with a slow-release melting agent, which comprises the following components in parts by mass: sodium chloride 50-70 parts, urea 20-30 parts, carboxymethyl cellulose 5-10 parts, and water 10-20 parts; the melting hole is injected with a strong melting agent, which comprises the following components in parts by mass: calcium chloride 40-60 parts, quicklime 20-35 parts, magnesium chloride hexahydrate 10-15 parts, and activated carbon powder 5-10 parts.

[0016] Preferably, in step S1, after the strong melting agent is injected into the melting hole, a thermal insulation layer is immediately covered, and after the slow-release melting agent is injected into the ice surface guide groove, it is exposed to the environment, so that the ice layer melting process is divided into two stages: in the first stage, the strong melting agent in the melting hole is isolated from the air under the action of the thermal insulation layer, and preferentially absorbs the heat of the ice layer to cause the ice ridge to melt first, so that each ice surface guide groove is connected to each other; in the second stage, the thickness difference of the slow-release melting agent in each ice surface guide groove causes the overall log raft to be subjected to a reverse torque around the axis parallel to the embankment, and sink along the slope; wherein the thermal insulation layer is a biomass board made of compressed straw.

[0017] Preferably, in step S4, the counterweight includes a fixed counterweight block and a detachable counterweight unit, the fixed counterweight block is fixed at the center position of the middle body part of the log raft unit, and the detachable counterweight block is attached to the edge position of the middle body part of the log raft unit through a water-soluble bandage, and the density gradient of the detachable counterweight block on each log raft unit increases along the embankment to the river direction; wherein the degradation period of the water-soluble bandage is configured to start degrading after the log raft unit enters the water, and completely break before the log raft unit touches the bottom, so that the detachable counterweight unit is detached before the log raft unit touches the bottom.

[0018] Preferably, the detachable counterweight block is a hollow sealed shell structure, which is filled with counterweight material, and the mass of the counterweight material filled in the detachable counterweight block on each log raft unit increases along the embankment to the river direction; the thickness of the water-soluble bandage is 0.5-2 mm, which comprises polyvinyl alcohol with a mass content of 60-80% and starch with a mass content of 20-40%.

[0019] Preferably, the middle body part of the log raft unit adopts a layered composite structure, which comprises, from bottom to top, in order:

[0020] The bottom buffer layer is woven by mixing coconut fiber and rubber particles, with a thickness of 3-5 cm;

[0021] The main load-bearing layer is woven by binding willow branches into willow bundles with a diameter of 8-12 cm, which are longitudinally and transversely crossed at an interval of 5-10 cm;

[0022] A top reinforcing layer composed of geogrid and nylon rope;

[0023] The fixed weight block is embedded at the willow branch intersection node of the main body load-bearing layer, and the detachable weight unit is fixed on the top reinforcing layer by a water-soluble bandage.

[0024] Preferably, the melting-promoting hole groove is inclined to the inclined hole of the adjacent ice surface guide groove, and the depth is 1 / 3 to 2 / 3 of the thickness of the ice layer.

[0025] Preferably, the flexible connection is connected by polypropylene material with an elongation greater than 30%.

[0026] Preferably, the number N of the ice surface guide grooves, the overall width W of the log row and the ice ridge width D satisfy:

[0027] N=W / A, A is 1.5 to 2.5, the calculation result is rounded, and the unit of W is m;

[0028] D=0.8~1.2×(W / N), the unit of D is m.

[0029] The present application at least includes the following beneficial effects:

[0030] Firstly, the present application realizes precise control of the sinking process of the log row by establishing the ice surface guide groove system and optimizing the structural parameters thereof, determines the number N of the grooves and the ice ridge width D according to the overall width W of the log row, ensures that each strip-shaped segmented row body obtains the best guiding effect, and guarantees the structural stability of the ice ridge, overcomes the randomness of the traditional empirical construction, enables the log row to sink along the preset path strictly, effectively solves the technical problems of row body deviation and distortion, greatly improves the positioning accuracy, provides a scientific and reliable design and construction standard for river protection engineering, and significantly improves the engineering quality.

[0031] Secondly, the present application realizes the ordered disintegration of the ice layer by using a differentiated melting-promoting agent formula and a staged melting control strategy, preferentially melts the ice ridge structure by using a strong melting-promoting agent, controls the melting progress of the groove by using a slow-release melting-promoting agent, and cooperates with the environment-friendly biomass board heat insulation layer to ensure that the log row unit maintains structural integrity in the initial sinking period, obtains sufficient overturning torque in the sinking process, and finally adheres to the slope surface in an ideal spreading posture, perfectly solving the problems of row body tearing and folding caused by uneven melting in the traditional construction.

[0032] Thirdly, the counterweight system designed by the application realizes dynamic optimization of the sinking process through the synergistic effect of the fixed counterweight and the detachable counterweight, and the gradient-distributed detachable counterweight units cooperate with the water-soluble binding belts with accurate degradation periods, which not only ensures sufficient driving force in the initial sinking stage, but also automatically reduces the weight before the body touches the bottom, effectively reduces the impact energy, solves the double problems of easy impact damage or sinking into silt in traditional construction, and significantly improves the reliability and safety of the project.

[0033] Fourthly, the layered composite structure of the application realizes multifunctional integration through the design of materials and structures, the bottom buffer layer effectively absorbs the bottom impact, the main bearing layer provides stable structural support, and the top reinforcing layer ensures the integrity, and the layers work together, not only improving the durability and adaptability of the body, but also fitting the irregular riverbed terrain well, providing more durable and effective protection for river protection, and prolonging the service life of the project.

[0034] Fifthly, the application optimizes the arrangement and connection mode of the melting hole slots, improves the overall performance of the system, the inclined melting hole slots increase the contact area with the ice layer, and improve the melting efficiency; the high ductility polypropylene connecting material has sufficient deformation adaptability, so that the whole timber pile can better adapt to complex site conditions, and ensure stable working performance under various working conditions, providing reliable protection for the smooth implementation of the project.

[0035] Other advantages, objects and features of the application will be partially embodied in the following description, and some will be understood by those skilled in the art through research and practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 Figure 1 is a schematic diagram of the arrangement of the ice ridge and the ice surface guide groove in one technical solution of the application;

[0037] Among them, 1, ice ridge; 2, ice surface guide groove; 3, melting hole slot. DETAILED DESCRIPTION

[0038] The application will be further described in detail below in combination with specific technical solutions, so that those skilled in the art can implement it according to the description.

[0039] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0040] As Figure 1 , the application provides a river dangerous work timber pile protection ice construction method, which comprises:

[0041] S1, on the frozen river ice surface, along the design laying position of the fender, a plurality of ice surface guide grooves 2 extending along the river direction are cut at intervals, ice ridges 1 are formed between adjacent ice surface guide grooves 2, and a plurality of melting holes 3 are arranged on the ice ridges 1, and melting agents are injected into the melting holes 3 and the guide grooves;

[0042] S2, a plurality of fender units suitable for the ice surface guide grooves 2 are prepared and laid, each fender unit including a middle body portion sunk into the ice surface guide groove and a side portion covering the surface of the ice ridge 1;

[0043] S3, on the ice ridge 1, the overlapping portions of adjacent fender units are flexibly connected, so that all fender units are connected as a whole above the ice surface;

[0044] S4, weights are applied to the middle body portions of the fender units in the ice surface guide grooves 2; when the ice layer melts, each fender unit slides and sinks to the designed laying position along the path defined by the ice surface guide groove 2 under the action of the weight;

[0045] Wherein, the thickness of the melting agent in the ice surface guide groove increases in the direction extending from the bank to the river, so that the side portions of adjacent fender units overlap up and down.

[0046] The above technical solution realizes active control of the sinking process of the fender through prefabricated ice surface structure and fender unit structure. In order to solve the problem that the sinking trajectory of the fender is uncontrollable in traditional ice construction, a plurality of parallel ice surface guide grooves 2 are cut along the design laying position of the fender on the frozen river ice surface, and ice ridge 1 structures are naturally formed between the grooves. The grooves provide a clear movement path for the fender unit, ensuring that each unit can move in the predetermined direction. The melting holes arranged on the ice ridge 1 and the melting agent in the ice surface guide groove 2 form a melting system together, which orderly guides the melting process of the ice layer and avoids the distortion or tearing of the fender caused by uneven melting in the traditional method. The middle body portion of each fender unit is sunk into the ice surface guide groove 2, and the side portions are covered on the surface of the ice ridge 1, so that a stable contact relationship is formed between the fender and the ice layer, and the special structure design of the fender unit further ensures the reliability of the construction. When adjacent fender units are flexibly connected to form a whole on the ice ridge 1, the integrity of the fender is ensured, and conditions are created for subsequent staged sinking. The increasing thickness of the melting agent in the direction from the bank to the river creates a differentiated melting environment, which generates a necessary overturning torque for the fender, guiding the fender to complete the sinking process in a more conforming posture.

[0047] In implementation, first, the ice surface guide groove 2 is accurately excavated on the ice surface, and the ice surface guide groove 2 is parallel to the extension direction of the river channel, so as to ensure that the log unit can smoothly slide along the river channel slope, and the ice ridge 1 is formed between adjacent ice surface guide grooves 2, and the melting hole groove is arranged on the ice ridge 1. The melting agent is respectively injected into the melting hole groove and the ice surface guide groove 2, and the thickness of the melting agent in the ice surface guide groove 2 gradually increases along the direction from the bank to the river channel. The laying of the log unit needs to ensure that the middle main part is accurately placed in the groove, the two side parts are evenly covered on the surface of the ice ridge 1, and the side edges of adjacent log units are overlapped and connected.

[0048] When the log unit is in place, the flexible connection operation is performed on the ice ridge 1, and the independent units are connected into a whole, which not only ensures the integrity of the log unit, but also allows each unit to have a certain degree of relative motion freedom during sinking. The counterweight is applied to the middle main part of the log unit in the groove, and a stable sinking driving force is provided. With the gradual melting of the ice layer under the action of the melting agent, the log unit begins to stably sink along the set path of the guide groove under the action of the counterweight. Due to the thickness gradient distribution of the melting agent, the log unit near the river channel side will obtain greater sinking driving force, thereby forming the required overturning motion, and ensuring that the log unit is settled in the designed position with an ideal posture.

[0049] The above technical solution changes the uncontrollable state of the log sinking process in the traditional ice construction, and ensures that the log can complete the sinking according to the designed path and predetermined posture through the guide groove system and differential melting agent arrangement, solves the technical problems of log body deviation and distortion that have long plagued engineering practice, and greatly improves the construction precision and reliability of the foot protection project. At the same time, through reasonable structure design and construction time sequence arrangement, the technical solution effectively protects the structural integrity of the log, avoids tearing or damage that may occur during construction, prolongs the service life of the project. The whole construction process does not need complex mechanical equipment or special construction conditions, and can be implemented in the conventional ice operation environment, has good practicability and popularization value, and provides a new technical means for river channel danger control.

[0050] In one of the technical solutions, the ice surface guide groove 2 is injected with a slow-release melting agent, which includes the following components in parts by mass: sodium chloride 50-70 parts, urea 20-30 parts, carboxymethyl cellulose 5-10 parts, and water 10-20 parts; the melting hole groove is injected with a strong melting agent, which includes the following components in parts by mass: calcium chloride 40-60 parts, quicklime 20-35 parts, magnesium chloride hexahydrate 10-15 parts, and activated carbon powder 5-10 parts. The strong melting agent uses the synergistic effect of calcium chloride and quicklime to produce a rapid melting effect at the ice ridge 1, while the slow-release melting agent realizes gradual melting in the guide groove through the gel matrix formed by carboxymethyl cellulose. The differentiated melting strategy effectively solves the problem of distortion of the timbering caused by asynchronous melting in traditional construction, ensuring that the ice ridge 1 is preferentially melted to create initial conditions for the sinking of the timbering, and ensuring that the slow-release melting in the groove guarantees the smooth sinking of the body along the predetermined trajectory, significantly improving the controllability and accuracy of the construction process.

[0051] In one of the technical solutions, in step S1, after injecting the strong melting agent into the melting hole groove, a thermal insulation layer is immediately covered, and after injecting the slow-release melting agent into the ice surface guide groove 2, it is exposed to the environment, so that the ice layer melting process is divided into two stages: the first stage, the strong melting agent in the melting hole groove is isolated from the air under the action of the thermal insulation layer, preferentially absorbs the heat of the ice layer, causing the ice ridge 1 to melt first, and the ice surface guide grooves 2 are connected to each other; the second stage, the thickness difference of the slow-release melting agent in each ice surface guide groove 2 causes the overall timbering to be subjected to a reversing moment around the axis parallel to the embankment, and sinks along the slope; wherein the thermal insulation layer is a biomass board made of compressed straw.

[0052] In the above technical solution, the biomass board made of compressed straw is used as a thermal insulation layer covering the melting hole groove, effectively blocking the heat exchange between the strong melting agent and the air, causing the melting agent to preferentially absorb the heat of the ice layer, and ensuring that the ice ridge 1 structure melts first, creating the necessary conditions for the connection of each ice surface guide groove 2. In the second stage, due to the increasing thickness of the slow-release melting agent in each ice surface guide groove 2 along the embankment towards the river direction, a differentiated melting speed gradient is formed, and the gradient distribution naturally generates a reversing moment that makes the overall timbering rotate around the axis parallel to the embankment. The above technical solution effectively solves the technical problems of body distortion and fracture caused by asynchronous melting in traditional ice construction, ensures the structural stability of the timbering unit in the early stage of sinking, and realizes the ideal fit of the body and the slope through scientific moment control, significantly improving the construction accuracy and reliability of the timbering protection project, providing a new technical approach for river danger management. At the same time, the use of biodegradable straw board as a thermal insulation material can naturally decompose after completing the insulation function, avoiding white pollution and demonstrating good environmental protection characteristics.

[0053] In one of the technical solutions, in step S4, the counterweight includes a fixed counterweight block and a detachable counterweight unit, the fixed counterweight block is fixed at the center position of the middle body part of the dam unit, and the detachable counterweight block is attached to the edge position of the middle body part of the dam unit through a water-soluble bandage, and the density gradient of the detachable counterweight block on each dam unit increases in the direction from the embankment to the river; wherein the degradation period of the water-soluble bandage is configured to start degrading after the dam unit enters the water and completely break before the dam unit touches the bottom, so that the detachable counterweight unit is separated before the dam unit touches the bottom.

[0054] The above technical solution optimizes the control of the sinking process of the dam by combining the fixed counterweight block and the detachable counterweight unit, wherein the fixed counterweight block is located at the center position of the dam unit to provide stable basic sinking force, and the detachable counterweight unit with increasing density gradient in the direction from the embankment to the river is attached to the edge position through the water-soluble bandage to form a differentiated sinking driving force distribution. Different counterweight layouts not only ensure that the dam unit obtains sufficient starting kinetic energy in the initial sinking stage, but also promote the overturning motion of the overall dam body rotating around the axis through the edge side effect. At the same time, the degradation period of the water-soluble bandage is accurately configured to start degrading after the dam unit enters the water and completely break before the dam unit touches the bottom, so that the detachable counterweight unit can automatically separate at the critical moment. The above technical solution effectively solves the double problems of the traditional construction that the dam body hits the riverbed or sinks into the silt due to the excessive overall weight, not only protects the integrity of the dam structure, but also ensures the accuracy of the final in-place posture, so that the dam can gently adhere to the riverbed surface in a more ideal weight state, greatly improving the actual effect and long-term stability of the foot protection project.

[0055] In one of the technical solutions, the detachable counterweight block is a hollow sealed shell structure, which is filled with counterweight material, and the mass of the counterweight material filled in the detachable counterweight block on each dam unit increases in the direction from the embankment to the river; the thickness of the water-soluble bandage is 0.5-2mm, which includes polyvinyl alcohol with a mass content of 60-80% and starch with a mass content of 20-40%. Through the hollow sealed shell structure of the detachable counterweight block and the accurate control of the water-soluble bandage parameters, the precise control of the sinking process is realized. The hollow shell design ensures the stable packaging of the counterweight material, and the increasing counterweight mass in the direction from the embankment to the river forms an ideal sinking driving force gradient. The water-soluble bandage realizes precise degradation timing matching the ice layer melting process through the specific ratio of polyvinyl alcohol and starch and the thickness control of 0.5-2mm. The above technical solution effectively solves the technical problem of the incoordination between the counterweight separation time and the sinking process, ensures that the detachable counterweight separates in time before the dam unit touches the bottom, not only guarantees sufficient driving force in the initial sinking stage, but also avoids excessive impact when the dam body is in place, significantly improves the construction precision and reliability.

[0056] In one of the technical solutions, the middle body part of the log unit adopts a layered composite structure, which includes, from bottom to top, in order:

[0057] The bottom buffer layer is woven by mixing coconut fiber and rubber particles, with a thickness of 3-5 cm;

[0058] The main load-bearing layer is woven by interlacing willow bundles with a diameter of 8-12 cm at an interval of 5-10 cm;

[0059] The top reinforcing layer is composed of geogrid and nylon rope;

[0060] Among them, the fixed weight block is embedded at the intersection node of the willow bundle of the main load-bearing layer, and the detachable weight unit is fixed on the top reinforcing layer by water-soluble bandage.

[0061] In the above technical solution, the bottom buffer layer is woven by mixing coconut fiber and rubber particles, effectively absorbing the impact energy when the body touches the bottom, preventing structural damage; the main load-bearing layer is woven by interlacing willow bundles, maintaining the flexibility of traditional materials and forming a stable load-bearing system through scientific weaving interval; the top reinforcing layer is composed of geogrid and nylon rope, ensuring the integrity and tensile strength of the body; the overall structure enables the log unit to better adapt to the changes in riverbed topography, while the complementary functions between the layers significantly improve the durability and protection effect of the body.

[0062] The layout of the fixed weight block embedded at the intersection node of the willow bundle ensures the stability of the weight and avoids local stress concentration; the detachable weight unit is fixed on the top reinforcing layer by water-soluble bandage, which is convenient for construction operation and does not affect the main structure. The above technical solution effectively solves the technical problems of easy damage and poor adaptability of traditional logs, enabling the body to maintain structural integrity during sinking and closely fit the riverbed surface after being in place. The selection of materials for each layer takes into account the engineering performance and ecological environmental requirements, providing more reliable technical support for river protection projects.

[0063] In one of the technical solutions, the melting-promoting hole slot is inclined to the adjacent ice surface guide groove 2, and the depth is 1 / 3-2 / 3 of the thickness of the ice layer. By setting the melting-promoting hole slot to be inclined to the adjacent guide groove and having a depth of 1 / 3-2 / 3 of the thickness of the ice layer, the contact area between the melting agent and the ice layer is significantly increased, the melting efficiency of the ice ridge 1 area is effectively improved, and the guide grooves are quickly connected, creating favorable conditions for the overall synchronous sinking of the log unit, thereby further enhancing the reliability and efficiency of the construction process.

[0064] In one of the technical solutions, the flexible connection is connected by polypropylene material with a ductility greater than 30%, which can adapt to different sinking speeds and displacement differences during the sinking process of each unit, effectively relieve the structural stress caused by uneven local stress, and ensure the integrity of the whole body while preventing the connection part from breaking.

[0065] In one of the technical solutions, the number N of ice surface guide grooves 2, the overall width W of the timber row, and the width D of the ice ridge 1 satisfy:

[0066] N=W / A, A is 1.5-2.5, the calculation result is rounded, and the unit of W is m;

[0067] D=0.8-1.2×(W / N), the unit of D is m.

[0068] The above technical solution realizes the standardized design of engineering parameters by establishing the quantitative relationship between the number of ice surface guide grooves 2, the overall width of the timber row, and the width of the ice ridge 1. The ratio relationship between the number of grooves N and the width W of the timber row ensures that each strip-shaped segmented row body can obtain the best guiding effect, avoiding the problems of too dense or too sparse grooves. The associated design of the width D of the ice ridge 1 and the number of grooves ensures that the ice ridge 1 has sufficient structural strength to withstand the construction load, while optimizing the material utilization efficiency. The above technical solution accurately calculates the number of grooves and the width of the ice ridge 1, which not only ensures the stability of the timber row unit during the sinking process, but also improves the construction efficiency and quality controllability, effectively solves the engineering quality problems caused by uncoordinated parameters in traditional construction, and significantly improves the standardization degree and reliability of the project.

[0069] Taking the timber row protection foot ice construction of a typical dangerous section of a river in a cold region as an example, the construction operation should be completed during the stable freezing period of the river. The ice layer thickness of this section is 40 cm, the design width of the timber row protection foot is 10 m, and the length along the river direction is 20 m. After the ice layer reaches sufficient bearing capacity, use mechanical ice drill, ice saw, etc. to measure and lay out on the ice surface, and mark the design laying position of the timber row.

[0070] First, 8 ice surface guide grooves 2 extending along the river are chiseled at intervals along the design position. The cross section of the groove is trapezoidal, the upper opening is 50 cm wide, the lower opening is 30 cm wide, and the depth is 25 cm. The center distance between adjacent grooves is 1.25 m, forming 7 ice ridges 1 with a width of 75 cm. On each ice ridge 1, a melting hole is chiseled at an interval of 1 m, the hole diameter is 10 cm, the depth is 25 cm, and the angle with the adjacent groove is 45°.

[0071] Two kinds of melting agents are prepared:

[0072] The first kind of melting agent is prepared by mixing 1 kg of water with 0.5 kg of sodium chloride and 0.5 kg of sodium sulfate, and the second kind of melting agent is prepared by mixing 1 kg of water with 0.5 kg of sodium chloride and 0.5 kg of sodium nitrate.Slow-release melting agent: take sodium chloride 60 parts, urea 25 parts, carboxymethyl cellulose 8 parts and water 15 parts to mix into gelatinous; strong melting agent: take calcium chloride 50 parts, quicklime 28 parts, magnesium chloride hexahydrate 12 parts and activated carbon powder 8 parts to mix evenly.

[0073] Prepare 8 strip-shaped log units, each unit is 20 m long and 1.25 m wide, and adopts a layered composite structure:

[0074] The bottom buffer layer is woven by mixing coconut fiber and rubber particles in a mass ratio of 7:3, with a thickness of 4 cm; the main load-bearing layer is woven by bundling willow branches into willow bundles with a diameter of 10 cm, with a longitudinal and transverse intersection interval of 8 cm; the top reinforcing layer is reinforced by composite of bidirectional geogrid and nylon rope net.

[0075] After filling the strong melting agent into the melting hole, immediately cover it with a 3 cm thick biomass board made of compressed straw as a thermal insulation layer, with a size of 30 cm x 30 cm, completely covering the hole and extending 10 cm beyond the edge; ensure that the heat exchange rate between the melting agent and the ice layer is very slow when the ambient temperature does not rise and the ice layer temperature is low, effectively inhibiting the reaction, and the ice ridge 1 remains stable. Inject the slow-release melting agent into the guide groove, and gradually increase the thickness of the melting agent from 3 cm to 8 cm along the embankment to the river direction, forming a thickness gradient, and expose it to the environment after injection.

[0076] Lay the log units one by one, with the middle main part sinking into the corresponding guide groove, and the two side parts each extending 25 cm to cover the surface of the ice ridge 1. Use a polypropylene net-shaped connecting belt with an elongation rate of 35% to bind and connect the overlapping parts of adjacent log units on the ice ridge 1, with a connection interval of 1 m, so that all the log units form a whole above the ice surface.

[0077] Arrange the counterweight system on each log unit:

[0078] Fixed counterweight block: a 20 kg concrete block embedded at the intersection node of the willow bundle, with one every 2 m along the longitudinal direction of the log unit; detachable counterweight unit: a hollow sealed plastic shell filled with counterweight material. Along the embankment to the river direction, the distribution density of the detachable counterweight units on each log unit increases from 2 / m to 5 / m, and the mass of a single counterweight unit increases from 5 kg to 15 kg. Fixed on the top reinforcing layer by a water-soluble binding belt with a thickness of 1.2 mm, which is made of polyvinyl alcohol with a mass content of 70% and starch with a mass content of 30%.

[0079] When the ambient temperature rises above 5℃, the ice layer begins to melt in stages according to the design. In the first stage, the strong ice-melting agent in the ice-melting hole absorbs the heat of the ice layer preferentially under the action of the heat preservation layer, and after 48 hours, the ice ridge 1 melts first and penetrates. In the second stage, the slow-release ice-melting agent in the guide groove melts differently due to the thickness difference, and after 72 hours, the log raft unit begins to slide down along the path guided by the groove under the action of the counterweight. When it sinks to 1m from the riverbed, the water-soluble bandage degrades and breaks, and can automatically separate from the counterweight unit. Finally, the log raft is precisely positioned in the spread posture, forming a continuous and complete foot protection structure.

[0080] According to the measurement, the deviation of the log raft positioning position from the design position is less than 15cm, the structure of the log raft is complete, there is no twisting and tearing phenomenon, and it completely meets the engineering design requirements and construction quality standards.

[0081] The number of devices and the scale of processing described here are used to simplify the description of the present application. It is obvious to those skilled in the art that the application of the river dangerous work log raft foot protection ice construction method can be modified and changed.

[0082] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application, and other modifications can be easily realized by those skilled in the art, therefore, the present application is not limited to specific details and specific technical solutions shown and described here, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A method for construction of a riverway danger-avoiding timber mattress toe protection on ice, characterized in that, The method comprises the following steps: S1. On the frozen river surface, design the laying position of the log raft, and space apart to dig a plurality of ice surface guide grooves extending along the river direction, and form ice ridges between adjacent ice surface guide grooves, and a plurality of melting holes are arranged on the ice ridges, and a melting agent is injected into the melting holes and the ice surface guide grooves; S2. A plurality of log raft units suitable for the ice surface guide grooves are prepared and laid, each log raft unit comprising a middle main part sunk into the ice surface guide groove and two side edge parts covering the surface of the ice ridge; S3. On the ice ridge, the overlapping parts of adjacent log raft units are flexibly connected, so that all the log raft units are connected as a whole above the ice surface; S4. A counterweight is applied to the middle main part of the log raft unit in the ice surface guide groove; when the ice layer melts, each log raft unit slides and sinks to the designed laying position along the path defined by the ice surface guide groove under the action of the counterweight; Wherein, the thickness of the melting agent in the ice surface guide groove increases in turn along the extension direction of the embankment to the river, so that the two side edge parts of adjacent log raft units overlap up and down; In step S1, after injecting the strong melting agent into the melting holes, a heat preservation layer is immediately covered, and after injecting the slow-release melting agent into the ice surface guide groove, it is exposed to the environment, so that the ice melting process is divided into two stages: in the first stage, the strong melting agent in the melting holes is isolated from the air under the action of the heat preservation layer, and preferentially absorbs the heat of the ice layer to cause the ice ridge to melt first, so that each ice surface guide groove is connected to each other; in the second stage, the thickness difference of the slow-release melting agent in each ice surface guide groove causes the overall log raft to be subjected to a reversed torque around the axis parallel to the embankment, and to sink along the slope; wherein, the heat preservation layer is a biomass board made of compressed straw; In step S4, the counterweight comprises a fixed counterweight block and a detachable counterweight block, the fixed counterweight block is fixed at the center position of the middle main part of the log raft unit, and the detachable counterweight block is attached to the edge position of the middle main part of the log raft unit through a water-soluble bandage, and the density gradient of the detachable counterweight block on each log raft unit increases along the embankment to the river direction; wherein, the degradation period of the water-soluble bandage is configured to start degrading after the log raft unit enters the water, and completely break before the log raft unit touches the bottom, so that the detachable counterweight block is detached before the log raft unit touches the bottom.

2. The method of claim 1, wherein the method further comprises: The melting agent injected into the ice surface guide groove is a slow-release melting agent, which comprises the following components in mass fraction: sodium chloride 50-70 parts, urea 20-30 parts, carboxymethyl cellulose 5-10 parts, and water 10-20 parts; the melting agent injected into the melting holes is a strong melting agent, which comprises the following components in mass fraction: calcium chloride 40-60 parts, quicklime 20-35 parts, magnesium chloride hexahydrate 10-15 parts, and activated carbon powder 5-10 parts.

3. The method of claim 2, wherein the method further comprises: The detachable counterweight is a hollow sealed shell structure filled with counterweight material, and the mass of the counterweight material filled in each of the detachable counterweight blocks on the fender units increases in the direction of the river channel along the embankment; the water-soluble bandage has a thickness of 0.5-2 mm and includes polyvinyl alcohol with a mass content of 60-80% and starch with a mass content of 20-40%.

4. The method of claim 3, wherein the method further comprises: The middle main body part of the fender unit adopts a layered composite structure, which includes, from bottom to top, a bottom buffer layer, a main load-bearing layer, and a top reinforcing layer. The bottom buffer layer is made of coconut fiber mixed with rubber particles and has a thickness of 3-5 cm. The main load-bearing layer is made of willow branches bundled into willow bundles with a diameter of 8-12 cm and woven in a longitudinal and transverse cross pattern at an interval of 5-10 cm. The top reinforcing layer is made of geogrid and nylon rope. The fixed counterweight blocks are embedded at the intersection nodes of the willow bundles of the main load-bearing layer, and the detachable counterweight blocks are fixed on the top reinforcing layer by water-soluble bandages.

5. The method of construction on ice for protecting the toe of a river training dike by means of a mattress according to claim 1, characterized in that, The melting-promoting hole slot is an inclined hole that is inclined toward the adjacent ice surface guide groove on the side of the ice ridge where it is located, and has a depth of 1 / 3-2 / 3 of the thickness of the ice layer.

6. The method of constructing a river hazard dike on ice according to claim 1, wherein The flexible connection is made of polypropylene material with an elongation rate greater than 30%.

7. The method of construction on ice for protecting the toe of an embankment of a river training works according to claim 6, wherein The number N of the ice surface guide grooves, the overall width W of the fender, and the width D of the ice ridge satisfy the following conditions: N = W / A, A is 1.5-2.5, the calculation result is rounded, and the unit of W is m; D = (0.8-1.2) × (W / N), and the unit of D is m.

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