Calculation method of riprap silt extrusion depth based on energy conservation

Abstract

The invention belongs to the technical field of road engineering roadbed treatment, and particularly relates to a riprap silt squeezing depth calculation method based on energy conservation. The calculation method comprises the following steps: S1, assuming a simplified calculation working condition, and respectively calculating gravitational potential energy of block stones and soil blocks by taking the block stones and wedge-shaped soil blocks at the lower part after the block stones enter a soil body as research objects; s2, calculating resistance work and buoyancy work of the block stone in water, side soil shear work of the block stone when the block stone moves in the sludge, and soil pressure and shear work of the soil block; s3, establishing a balance equation of the total potential energy and the total resistance acting; and S4, calculating the riprap silt squeezing depth according to the equation. According to the method, the problem of establishment of the balance equation in the overwater riprap process is solved by utilizing the principle of conservation of energy, the design difficulty of engineers and the extra workload of parameter valuing are effectively reduced on the basis of ensuring the calculation requirement, and the scheme decision-making efficiency is favorably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of road engineering roadbed treatment, and in particular relates to a method for calculating the depth of riprap and silt squeezing based on energy conservation. Background Art

[0002] Riprap is an effective method for treating soft soil foundation, especially for treating the underlying soft foundation of dams, roads and other projects, in order to improve the bearing capacity of the foundation and reduce post-construction settlement.

[0003] Chinese patent CN117290919A (publication date: December 26, 2023) discloses a technology for the evolution and rapid evaluation of the silt-squeezing morphology of soft foundation dumping in ponds and lakes. The evaluation technology includes the construction of soft foundation dumping and silt-squeezing in ponds and lakes and the rapid evaluation of the silt-squeezing morphology at the construction site; the rapid evaluation of the silt-squeezing morphology at the construction site is to scan and reconstruct the silt-squeezing morphology after dumping, obtain its evolution process and evolution characteristics, and quickly evaluate the construction effect based on the evolution characteristics. This patent mainly evaluates the dumping and silt-squeezing morphology during the construction period. The patent has limited usage scenarios and cannot provide an estimated silt-squeezing depth in the scheme comparison stage.

[0004] Chinese patent CN110306522A (publication date: April 7, 2023) discloses a method for predicting the depth of subsidence caused by explosive silt squeezing and stone filling. This patent is mainly used to predict the depth of subsidence caused by explosive silt squeezing and stone filling in foundation. This patent is only used for prediction in construction processes using explosive silt squeezing and cannot be used to predict the depth of silt squeezing in stone-throwing and silt squeezing construction processes.

[0005] There are currently two methods for calculating the depth of silt extrusion caused by riprap. The first method is the calculation of silt extrusion depth based on the limit equilibrium theory. This method assumes that the riprap body is a rigid foundation structure, which is quite different from typical granular foundations such as riprap, and does not consider the dynamic impact silt extrusion effect of the riprap process. The second method uses the energy conservation method to consider the depth of the stone when it rolls down from above to the silt. However, this method uses the side resistance and end resistance parameters of the pile foundation when calculating the work done by the silt resistance. The value of this parameter is quite arbitrary and has a great impact on the result. In addition, this method does not consider the influence of water depth when riprap is performed on water.

[0006] From the existing comparative cases, it can be seen that how to establish a set of appropriate equilibrium equations for calculating the depth of stone-throwing and silt-extrusion, provide an estimated silt-extrusion depth for the stone-throwing and silt-extrusion scheme selection stage, and improve the efficiency of scheme decision-making is a technical problem that has not yet been solved in this field. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a method for calculating the depth of riprap and silt squeezing based on energy conservation, which can comprehensively consider and realize the calculation of the depth of riprap and silt squeezing. The technical solution is as follows:

[0008] A method for calculating the depth of riprap and silt squeezing based on energy conservation, the method comprising the following steps:

[0009] Step S1, assuming a simplified calculation condition, taking the block stone and the wedge-shaped soil block at the lower part after entering the soil body as the research object, and calculating the gravitational potential energy of the block stone and the gravitational potential energy of the wedge-shaped soil block respectively;

[0010] Step S2, calculating the resistance work and buoyancy work of the stone in water, the shear work of the side soil when the stone moves in the mud, and the soil pressure and shear work of the wedge-shaped soil block;

[0011] Step S3, establishing a balance equation of the total potential energy and the work done by the total resistance;

[0012] Step S4, calculating the depth of riprap and silt dissipation according to the equation.

[0013] Furthermore, the step S1 assumes simplified calculation conditions including: assuming that the stone is a cube and ignoring the energy loss caused by the shape of the stone and the smoothness of the surface; assuming that the stone sinks forward during the sinking process and the stone does not tilt; assuming that there is no heat loss of energy in the stone during the sinking process; assuming that there is no energy loss when the stone collides with the stone; assuming that no initial velocity is applied to the stone when the backhoe bucket reverses; assuming that the stone ignores the resistance in the air, assuming that the stone ignores the water resistance in the water, and assuming that the stone ignores the frictional resistance of the side mud when sinking in the mud.

[0014] Furthermore, in step S1, it is assumed that the wedge-shaped soil block formed at the bottom after the stone enters the silt forms an angle of 45-60 degrees with the horizontal plane.

[0015] Furthermore, in step S1, it is assumed that the wedge-shaped soil block and the stone block sink synchronously.

[0016] Furthermore, in step S1, it is assumed that the soil on the side of the wedge-shaped soil block is subjected to the vertical component of pressure and the vertical component of friction.

[0017] Furthermore, in the calculation method, the gravitational potential energy of the block of stone is the starting point of the free fall of the block of stone from the bucket flipping, and the sum of the gravitational potential energy of the block of stone and the gravitational potential energy of the wedge-shaped soil block includes the following calculation contents:

[0018] The total gravitational potential energy of the block is calculated by the equation: r gv(h1+h2+h3);

[0019] The calculation equation of the gravitational potential energy of the wedge-shaped soil block is: s gh3;

[0020] The combined gravitational potential energy of the block and the tetrahedral wedge-shaped soil block is: rgv(h1+h2+h3)+γ s gh3;

[0021] Among them, γ r is the density of the rock, g is the acceleration of gravity, v is the volume of the rock, h1 is the height of the falling body in the air; h2 is the water depth; h3 is the silt squeezing depth, γ s is the density of silt.

[0022] Furthermore, the total resistance of the block of stone and the wedge-shaped soil block when sinking in the silt in the calculation method includes the following calculation contents:

[0023] The work done by the side resistance of the block is:

[0024] The soil wedge slope is subjected to soil pressure and does work:

[0025] The work done by the soil shear force on the slope of the soil wedge is:

[0026] The work done by the water resistance: f w A1h2;

[0027] The buoyancy work: ρ w b3h2;

[0028] The total resistance:

[0029] Where k0 is the static earth pressure coefficient of silt, k p is the passive earth pressure coefficient of silt, b is the side length of the block, c is the cohesion of silt, is the internal friction angle of the silt, A1 is the area of ​​the stone perpendicular to the moving path, ρ w is the density of water, f w Water resistance coefficient.

[0030] Furthermore, the balance equation of total potential energy and total resistance work established in the calculation method is:

[0031]

[0032] Among them, γ r is the density of the rock; g is the acceleration of gravity; v is the volume of the rock; γ s is the density of silt; k0 is the static earth pressure coefficient of silt; k p is the passive earth pressure coefficient of silt; b is the side length of the block; c is the cohesion of silt; is the internal friction angle of the silt; A1 is the area of ​​the stone perpendicular to the moving route; f w is the water resistance coefficient; ρw is the density of water; h1 is the height of the falling object in the air; h2 is the water depth; h3 is the silt squeezing depth.

[0033] Furthermore, in the calculation method, the depth h3 of riprap and silt discharging is calculated based on the established balance equation of total potential energy and work done by total resistance.

[0034] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0035] 1. The present invention provides a method for calculating the depth of riprap based on the energy conservation principle. It adopts the energy conservation principle for the first time to establish the equilibrium equation in the process of riprap on water. It comprehensively considers the influence of factors such as the weight of the stone, the height of the riprap, the water depth, the silt density, the cohesion, the internal friction angle, etc.

[0036] 2. The present invention provides a method for calculating the depth of riprap and silt squeezing based on the law of conservation of energy. The cohesion and internal friction angle of the silt selected in the calculation are the most common soil mechanics parameters in engineering practice. On the basis of ensuring the calculation requirements, it effectively reduces the design difficulty of engineers and the additional workload of parameter selection.

[0037] 3. The present invention provides a method for calculating the depth of riprap and silt squeezing based on the law of conservation of energy. In the invention, the stone blocks and the wedge-shaped soil blocks at the lower part after they enter the soil body are taken as research objects, and the gravitational potential energy of the stone blocks and the gravitational potential energy of the wedge-shaped soil blocks are calculated respectively, and the resistance of these two parts is calculated respectively. The force mechanism and logic of the combination are clear, and the calculation method can be better understood and accepted by engineers.

[0038] 4. The present invention provides a method for calculating the depth of riprap and silt-squeezing based on the law of energy conservation. The depth of riprap and silt-squeezing can be estimated based on the existing construction equipment and machine energy. The required depth of riprap and silt-squeezing can also be calculated based on the foundation stability and bearing capacity to calculate the free fall height of the block, thereby ensuring that the project can meet the stability requirements. The silt-squeezing depth can be estimated in advance during the scheme comparison stage, which is conducive to improving the efficiency of scheme decision-making.

[0039] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application so that it can be implemented in accordance with the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings as follows.

[0040] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0042] Figure 1 :Calculation method of riprap silt-squeezing depth;

[0043] Figure 2 : Schematic diagram of the process of riprap and silt extrusion;

[0044] Figure 3 : Force analysis diagram of a single stone sinking;

[0045] in:

[0046] L1 is the free-falling position of the rock after the bucket is turned over; L2 is the position of the rock after it falls freely to the water surface; L3 is the position where the rock is accelerated by the water resistance and continues to fall to the mud surface; L4 is the final position of the rock suspended in the mud or touching the bottom (the mud is shallow); is the internal friction angle of silt; h1 is the height of the falling body in the air; h2 is the water depth; h3 is the silt squeezing depth; σ is the normal stress on the surface of the stone or the surface of the silt wedge; τ is the shear stress on the surface of the stone or the surface of the silt wedge. Specific embodiments

[0047] To make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, rather than all of the embodiments. In the following description, specific details such as specific configuration and components are provided only to help fully understand the embodiments of the present application. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, for clarity and brevity, the description of known functions and structures is omitted in the embodiment.

[0048] It should be understood that the references to "one embodiment" or "this embodiment" throughout the specification mean that the specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present application. Therefore, the references to "one embodiment" or "this embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0049] In addition, the present application may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0050] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" in this article describes another type of association object relationship, indicating that there can be two relationships. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the previous and next associated objects are in an "or" relationship.

[0051] The term "at least one" in this article is merely a description of the association relationship of associated objects, indicating that there may be three relationships. For example, at least one of A and B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0052] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusions.

[0053] Embodiment 1:

[0054] This embodiment provides a method for calculating the depth of riprap based on energy conservation. Figure 1 As shown, the operation process includes four steps:

[0055] Step S1, assuming a simplified calculation condition, taking the block stone and the wedge-shaped soil block at the lower part after entering the soil body as the research object, and calculating the gravitational potential energy of the block stone and the gravitational potential energy of the wedge-shaped soil block respectively;

[0056] Step S2, calculating the resistance work and buoyancy work of the stone in water, the shear work of the side soil when the stone moves in the mud, and the soil pressure and shear work of the wedge-shaped soil block;

[0057] Step S3, establishing a balance equation of the total potential energy and the work done by the total resistance;

[0058] Step S4, calculating the depth of riprap and silt dissipation according to the equation.

[0059] The technical effect achieved by this embodiment is as follows: the present invention provides a method for calculating the depth of riprap and silt removal based on the law of conservation of energy, which can estimate the depth of riprap and silt removal according to the energy of existing construction equipment and machinery. This calculation method can estimate the silt removal depth in advance during the riprap and silt removal scheme comparison stage, which is beneficial to improving the efficiency of scheme decision-making.

[0060] Embodiment 2:

[0061] Based on Example 1, this embodiment provides a schematic diagram of the riprap and silt squeezing process for calculating the riprap and silt squeezing depth based on energy conservation. Figure 2 As shown in the figure, the analysis of the riprap and silt squeezing process is as follows:

[0062] When throwing stones on water, a hydraulic backhoe is used to grab the stone to a height of L1 to obtain potential energy, and then the bucket is turned over, and the stone falls freely to the water surface L2. The stone is affected by the water resistance in the water, and the acceleration decreases and continues to fall to the mud surface L3. When the stone contacts the mud surface, the potential energy of the stone is converted into kinetic energy for squeezing silt, and it sinks due to squeezing and shearing with the silt. During the sinking process, the side and cross section of the stone are respectively subjected to the side friction and end friction of the silty soil. Since the resistance of the silt is much greater than the water resistance, the energy consumption rate of the stone is accelerated. Finally, when the energy is consumed, the stone stabilizes at an elevation of L4, suspended in the silt or touching the bottom (the silt is shallow). The silt on the upper part of the completed stone is squeezed away, the silt thickness is reduced, and the subsequent stone is subjected to less silt resistance, which will collide with the previous stone, pushing the previous stone to continue sinking and squeezing silt. Repeat this process until the riprap foundation is stable in the silt.

[0063] According to the principle of conservation of energy, the equilibrium equation of gravitational potential energy and resistance work is established. Taking the starting point of the free fall of the rock from the bucket flipping, the distance that the rock ABCD falls from the air to the water surface is h1, the water depth is h2, and the final sinking distance of the rock in the mud is h3. The total sinking distance of the rock is h1+h2+h3. When the rock sinks in the mud, there will be a four-sided pyramid-shaped soil wedge at the bottom to form a combination with the rock and sink synchronously. The sinking height of the soil wedge is h3. During the sinking process, the resistance of the rock in the air is ignored. The rock is affected by water resistance in the water. When the rock sinks in the mud, it is affected by the friction resistance of the mud on the side, as well as the vertical component of the soil pressure on the side of the soil wedge and the vertical component of the friction resistance. Therefore, when the rock goes from free fall to stability in the mud, the gravitational work and resistance work of the combination are balanced.

[0064] The technical effect achieved by this embodiment is that the cohesion and internal friction angle of the silt selected in the calculation of the present invention are the most common soil mechanics parameters in engineering practice, which effectively reduce the design difficulty of engineers and the additional workload of parameter selection on the basis of ensuring the calculation requirements.

[0065] Embodiment 3:

[0066] Based on Examples 1 and 2, this example provides a method for calculating the depth of riprap based on energy conservation. Figure 3 As shown, the operation process includes four steps:

[0067] The method consists of the following steps:

[0068] Step S1, assuming a simplified calculation condition, taking the block stone and the wedge-shaped soil block at the lower part after entering the soil body as the research object, and calculating the gravitational potential energy of the block stone and the gravitational potential energy of the wedge-shaped soil block respectively;

[0069] Step S2, calculating the resistance work and buoyancy work of the stone in water, the shear work of the side soil when the stone moves in the mud, and the soil pressure and shear work of the wedge-shaped soil block;

[0070] Step S3, establishing a balance equation of the total potential energy and the work done by the total resistance;

[0071] Step S4, calculating the depth of riprap and silt dissipation according to the equation.

[0072] Furthermore, the step S1 assumes simplified calculation conditions including: assuming that the stone is a cube and ignoring the energy loss caused by the shape of the stone and the smoothness of the surface; assuming that the stone sinks forward during the sinking process and the stone does not tilt; assuming that there is no heat loss of energy in the stone during the sinking process; assuming that there is no energy loss when the stone collides with the stone; assuming that no initial velocity is applied to the stone when the backhoe bucket reverses; assuming that the stone ignores the resistance in the air, assuming that the stone ignores the water resistance in the water, and assuming that the stone ignores the frictional resistance of the side mud when sinking in the mud.

[0073] Furthermore, in step S1, it is assumed that the wedge-shaped soil block formed at the bottom after the stone blocks enter the silt forms an angle of 45-60 degrees with the horizontal plane.

[0074] Furthermore, in step S1, it is assumed that the wedge-shaped soil block and the stone block sink synchronously.

[0075] Furthermore, in step S1, it is assumed that the side surface of the wedge-shaped soil block is subjected to the vertical component of the soil pressure and the vertical component of the soil friction.

[0076] Furthermore, in the calculation method of step S1, the gravitational potential energy of the block of stone is calculated from the starting point of the free fall of the block of stone from the bucket flipping, and the sum of the gravitational potential energy of the block of stone and the gravitational potential energy of the wedge-shaped soil block includes the following calculation contents:

[0077] The total gravitational potential energy of the block is calculated by the equation: r gv(h1+h2+h3);

[0078] The gravitational potential energy calculation equation of the wedge-shaped soil block is: s gh3;

[0079] The combined gravitational potential energy of the block and the tetrahedral wedge-shaped soil block is: r gv(h1+h2+h3)+γ s gh3;

[0080] Among them, γ r is the density of the rock, g is the acceleration of gravity, v is the volume of the rock, h1 is the height of the falling body in the air; h2 is the water depth; h3 is the silt squeezing depth, γ s is the density of silt.

[0081] Furthermore, the total resistance of the block of stone and the wedge-shaped soil block when sinking in the silt in the calculation method of step S2 includes the following calculation contents:

[0082] The work done by the side resistance of the block is:

[0083] The soil wedge slope is subjected to soil pressure and does work:

[0084] The work done by the soil shear force on the slope of the soil wedge is:

[0085] The work done by the water resistance: f w A1h2;

[0086] The buoyancy work: ρ w b3h2;

[0087] The total resistance:

[0088] Where k0 is the static earth pressure coefficient of silt, k p is the passive earth pressure coefficient of silt, b is the side length of the block, c is the cohesion of silt, is the internal friction angle of the silt, A1 is the area of ​​the stone perpendicular to the moving path, ρ w is the density of water, f w Water resistance coefficient.

[0089] Furthermore, the balance equation of total potential energy and total resistance work established in the calculation method of step S3 is:

[0090]

[0091] Among them, γ r is the density of the rock; g is the acceleration of gravity; v is the volume of the rock; γ s is the density of silt; k0 is the static earth pressure coefficient of silt; k p is the passive earth pressure coefficient of silt; b is the side length of the block; c is the cohesion of silt; is the internal friction angle of the silt; A1 is the area of ​​the stone perpendicular to the moving route; f w is the water resistance coefficient; ρ w is the density of water; h1 is the height of the falling object in the air; h2 is the water depth; h3 is the silt squeezing depth.

[0092] Furthermore, the equilibrium equation in the calculation method of step S4 is used to calculate the depth of riprap to squeeze out silt; the depth of riprap to squeeze out silt is h3.

[0093] The technical effect achieved by this embodiment is that the calculation method in the present invention can estimate the depth of riprap and silt squeezing according to the existing construction equipment and machine energy, and can also calculate the free fall height of the block stone according to the required riprap and silt squeezing depth calculated according to the foundation stability and bearing capacity, thereby ensuring that the project can meet the stability requirements. The silt squeezing depth can be estimated in advance in the scheme comparison stage, which is conducive to improving the efficiency of scheme decision-making.

[0094] Embodiment 4:

[0095] Based on Examples 1-3, this example provides the measured silt-squeezing depth results of riprap at the lower part of a breakwater project in Shanghai, and compares the calculation process and results of the riprap silt-squeezing depth calculation formula provided in this application with the measured results in Table 1.

[0096] Table 1 lists the measured depth of riprap and silt squeezing at the bottom of a breakwater project in Shanghai. There are 5 sections in total, and the 5 sections are evenly distributed on the longitudinal section of the breakwater; 3 points are taken in each section, with a total of 15 drilling points. Point 1 is located near the land side, and the weight of the riprap is about 100kg; Point 2 is located in the middle of the riprap and silt squeezing foundation, and the weight of the riprap is about 200kg; Point 3 is located on the outer sea side of the riprap and silt squeezing foundation, which plays the role of a foot presser, and the weight of the riprap is about 600kg.

[0097] The data is the depth of the block sample below the designed desilting surface line in the actual drilling sampling. Due to factors such as the lower soil quality index after desilting during the construction process and measurement errors, the actual measured data of some points are small, but it does not affect the applicability of the calculation. The three points with a depth of 0 are caused by the deviation between the drilling point and the desilting line.

[0098] Table 1 The measured silt-squeezing depth of the lower breakwater of a project in Shanghai

[0099] Point location weight Section 1 Section 2 Section 3 Section 4 Section 5 average No. 1 (mud surface -1.5) 100kg 0.59 0 2.5 0.47 3.03 1.64 No. 2 (mud surface-2.0) 200kg 1.86 2.41 1.39 2.68 1.17 1.9 No. 3 (mud surface -1.5) 600kg 3.05 2.08 0 2.65 0 2.59

[0100] (Note: The normal water depth in the project area is 4m, and the low tide depth is 2m.)

[0101] The calculation process and results of the formula for calculating the depth of riprap based on energy conservation provided by the present invention are as follows: the falling height of the rock in the air is 2m, the water depth is 2m, and the density of the rock is 2700kg / m 3 , weight is 214kg, silt density is 1400kg / m 3 , when the cohesion of the silt is 4kPa and the internal friction angle is 5 degrees, it can be calculated that the depth of the riprap to squeeze the silt is 2.59m. At this time, the potential energy of the block accounts for 96.7% of the total potential energy, and the potential energy of the soil wedge accounts for 3.3%. In the total work done by the resistance, the work done by the side resistance of the block accounts for 68%, the sum of the resistance work of the soil wedge is 25.6%, the resistance work of the water is 4.95%, and the work done by the buoyancy is 1%.

[0102] The result is compared with the measured silt squeezing depth results of the riprap at the bottom of a breakwater project in Shanghai in Table 1. It can be seen that the average data of the silt squeezing depth in the table is basically consistent with the range of the calculation results of the present invention, and the calculation results are within the range of the measured results, which shows that the calculation method provided by the present invention is reliable and reasonable.

[0103] The technical effect achieved by this embodiment is: for the first time, the principle of conservation of energy is used to establish the equilibrium equation in the process of riprap on water, and the calculation formula comprehensively considers the influence of factors such as the weight of the stone, the height of the riprap, the water depth, the silt density, the cohesion, the internal friction angle, etc., and achieves the effect of simplifying the calculation content on the basis of meeting the needs of engineering estimation.

[0104] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for calculating the depth of riprap based on energy conservation, characterized in that: The method consists of the following steps: Step S1, assuming a simplified calculation condition, taking the block stone and the wedge-shaped soil block at the lower part after entering the soil body as the research object, and calculating the gravitational potential energy of the block stone and the gravitational potential energy of the wedge-shaped soil block respectively; Step S2, calculating the resistance work and buoyancy work of the stone in water, the shear work of the side soil when the stone moves in the mud, and the soil pressure and shear work of the wedge-shaped soil block; Step S3, establishing a balance equation of the total potential energy and the work done by the total resistance; Step S4, calculating the depth of riprap and silt dissipation according to the equation.

2. The method for calculating the depth of riprap and silt removal based on energy conservation according to claim 1 is characterized in that: The step S1 assumes simplified calculation conditions including: assuming that the stone is a cube and ignoring the energy loss caused by the shape of the stone and the smoothness of the surface; assuming that the stone sinks forward during the sinking process and the stone does not tilt; assuming that there is no heat loss of energy in the stone during the sinking process; assuming that there is no energy loss when the stones collide with each other; assuming that no initial velocity is applied to the stone when the backhoe bucket reverses; assuming that the stone ignores the resistance in the air, assuming that the stone ignores the water resistance in the water, and assuming that the stone ignores the friction resistance of the side mud when sinking in the mud.

3. The method for calculating the depth of riprap and silt removal based on energy conservation according to claim 2 is characterized in that: In the step S1, it is assumed that the wedge-shaped soil block formed at the bottom after the stone enters the silt forms an angle of 45-60 degrees with the horizontal plane.

4. The method for calculating the depth of riprap and silt removal based on energy conservation according to claim 3 is characterized in that: In step S1, it is assumed that the wedge-shaped soil block and the stone block sink synchronously.

5. The method for calculating the depth of riprap and silt removal based on energy conservation according to claim 4 is characterized in that: In step S1, it is assumed that the side surface of the wedge-shaped soil block is subjected to the vertical component of the soil pressure and the vertical component of the soil friction.

6. The method for calculating the depth of riprap based on energy conservation according to claim 5 is characterized in that: In the calculation method of step S1, the gravitational potential energy of the block of stone is calculated from the position where the block of stone starts to fall freely from the bucket flipping. The sum of the gravitational potential energy of the block of stone and the gravitational potential energy of the wedge-shaped soil block includes the following calculation contents: The total gravitational potential energy of the block is calculated by the equation: r gv(h1+h2+h3); The calculation equation of the gravitational potential energy of the wedge-shaped soil block is: s gh3; The combined gravitational potential energy of the block and the tetrahedral wedge-shaped soil block is: r gv(h1+h2+h3)+γ s gh3; Among them, γ r is the density of the rock, g is the acceleration of gravity, v is the volume of the rock, h1 is the height of the falling body in the air; h2 is the water depth; h3 is the silt squeezing depth, γ s is the density of silt.

7. The method for calculating the depth of riprap and silt removal based on energy conservation according to claim 5 is characterized in that: The total resistance of the block of stone and the wedge-shaped soil block when sinking in the silt in the calculation method of step S2 includes the following calculation contents: The work done by the side resistance of the block is: The soil wedge slope is subjected to soil pressure and does work: The work done by the soil shear force on the slope of the soil wedge is: The work done by the water resistance: f w A1h2; The buoyancy work: ρ w b3h2; The total resistance: Where k0 is the static earth pressure coefficient of silt, k p is the passive earth pressure coefficient of silt, b is the side length of the block, c is the cohesion of silt, is the internal friction angle of the silt, A1 is the area of ​​the stone perpendicular to the moving path, ρ w is the density of water, f w Water resistance coefficient.

8. The method for calculating the depth of riprap and silt removal based on energy conservation according to claim 5 is characterized in that: The equilibrium equation of total potential energy and total resistance work established in the calculation method of step S3 is: Among them, γ r is the density of the rock; g is the acceleration of gravity; v is the volume of the rock; γ s is the density of silt; k0 is the static earth pressure coefficient of silt; k p is the passive earth pressure coefficient of silt; b is the side length of the block; c is the cohesion of silt; is the internal friction angle of the silt; A1 is the area of ​​the stone perpendicular to the moving route; ρ w is the density of water; h1 is the height of the falling object in the air; h2 is the water depth; h3 is the silt squeezing depth.

9. The method for calculating the depth of riprap and silt removal based on energy conservation according to claim 8 is characterized in that: The equilibrium equation in the calculation method of step S4 is used to calculate the depth of riprap to squeeze out silt; the depth of riprap to squeeze out silt is h3.

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