CN115618593A - Method for predicting sinking depth of collapsed hard shell under wave action - Google Patents
Method for predicting sinking depth of collapsed hard shell under wave action Download PDFInfo
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- CN115618593A CN115618593A CN202211233723.7A CN202211233723A CN115618593A CN 115618593 A CN115618593 A CN 115618593A CN 202211233723 A CN202211233723 A CN 202211233723A CN 115618593 A CN115618593 A CN 115618593A
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/24—Earth materials
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V9/00—Prospecting or detecting by methods not provided for in groups G01V1/00 - G01V8/00
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
Abstract
The invention provides a method for predicting sinking depth of a collapsed hard shell under the action of waves, which comprises the following steps: determining the thickness z of the crust layer 1 The water depth d; determination of the non-drainage shear strength c of the crust soil u (ii) a Determining the severity of the crust 1 And heavy gamma of lower weak soil 2 (ii) a Determining the cohesive force c of a weak soil body at the lower part of a hard shell layer; determining wave parameters including wave height H and wavelength L at the hard shell layer under extreme sea conditions; determining the pressure limit p of the wave against the crust 0 (ii) a Determining the average pressure p of the waves in the collapsed block range 1 (ii) a Determining the edge length B of the collapsed block; determining the dead weight G of a collapsed block of the hard shell layer; determining collapse of crust under the action of wavesThe depth of the trap h.
Description
Relates to the field of
The invention relates to the field of ocean engineering, in particular to a method for predicting sinking depth of a collapsed hard shell under the action of waves.
Technical Field
A crust is a geological structure that develops in a sub-sea surface formation and is stronger than the underlying formation. When extreme sea conditions such as storm surge, typhoon and the like occur, the wave action is strong, the stratum at the lower part of the hard shell layer is softened or liquefied due to low strength, and the hard shell layer is high in strength and not easy to liquefy. At this time, the strength of the lower soil body is reduced, the supporting force is reduced, the lower soil body is easy to tear under the action of self weight and wave load to form collapsed blocks, and the collapsed blocks further sink under the action of the wave load. The sinking depth is definite, and the method has important significance for analyzing the influence of the sinking depth on ocean engineering, and defining the evolution structure of the seabed stratum and the like. No method has been seen to determine the sag depth so far.
Disclosure of Invention
The invention aims to solve the main technical problem of providing a method for predicting sinking depth of collapsed hard shell under the action of waves, and the method has the advantages of strong flow and reliable result.
In order to solve the technical problem, the invention provides a method for predicting sinking depth of a collapsed hard shell under the action of waves, which comprises the following steps:
(1) Determining the thickness z of the crust layer 1 The water depth d;
(2) Determination of the non-drainage shear strength c of the crust soil u ；
(3) Determining the severity of the crust 1 And the heavy gamma of the lower weak soil body 2 ；
(4) Determining the cohesive force c of a weak soil body at the lower part of a hard shell layer;
(5) Determining wave parameters including wave height H and wavelength L at the hard shell layer under extreme sea conditions;
(6) Determining the pressure limit p of the wave against the crust 0 ：
Wherein, γ w Taking 10.25kN/m for the seawater gravity 3 ；
(7) Determining the average wave pressure p in the collapsed area 1 ：
B is the side length of the collapsed block, and is a parameter to be solved;
(8) Determining the edge length B of the collapsed block;
solving equation and determining collapsed block edge length B, p 1 B＝4z 1 c u Taking the smaller of the results;
(9) Determining the dead weight G of a collapsed block of the hard shell layer;
G＝B 2 z 1 γ 1
(10) Determining the subsidence depth h of the collapsed crust block under the action of waves:
solving an equation, determining the subsidence depth h,
(B 2 +4Bh)c+γ 2 B 2 h＝B 2 p 1 +G
in a preferred embodiment: drilling at the crust in step 1, determining the thickness z of the crust using the drilling result 1 (ii) a And measuring the water depth at the hard shell layer by using a water depth measuring tool to determine the water depth d at the hard shell layer.
In a preferred embodiment: step 2, transporting the undisturbed soil sample taken out by drilling of the hard shell layer back to a laboratory for a miniature cross plate shear test to determine the non-drainage shear strength c of the soil body of the hard shell layer u 。
In a preferred embodiment: in the step 3, the undisturbed soil samples taken out by drilling the hard shell layer and the soft soil body at the lower part are transported back to a laboratory for density test, and after the densities are respectively tested, the densities are respectively multiplied by the gravity acceleration to obtain the heavy gamma of the hard shell layer 1 And the heavy gamma of the lower weak soil body 2 。
In a preferred embodiment: and 4, taking out an undisturbed soil sample from the weak soil body at the lower part, transporting the undisturbed soil sample back to a laboratory for direct shear test, and testing the cohesive force c of the undisturbed soil sample.
In a preferred embodiment: and 5, determining wave parameters including wave height H and wavelength L when the hard shell is in an extreme sea state according to actual measurement data or theoretical calculation.
The working principle of the invention is that when waves act on the hard shell layer, the hard shell layer has higher strength and is not easy to liquefy, the lower weak soil body has lower strength and is easy to liquefy, and once liquefied, the lower part of the upper hard shell layer soil body loses support, thereby collapsing blocks. And solving the size of the collapsed block by utilizing a mechanical balance principle. And then calculating the wave pressure borne by the collapsed block and the dead weight of the collapsed block, wherein the collapsed block sinks under the forces of the wave pressure and the dead weight, and the support force and the buoyancy of the soil body at the bottom of the collapsed block prevent the collapsed block from sinking, and further obtaining the sinking depth of the collapsed block according to a mechanical balance method. Therefore, the method has the advantages of strong flow and reliable result.
Detailed Description
The technical scheme in the embodiment of the invention is clearly and completely described below; it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work are within the scope of the present invention.
In the description of the present invention, it should be noted that, unless otherwise specifically stated or limited, the terms "mounted," "disposed," "sleeved/connected," "connected," and the like, should be construed broadly, such as "connected," which may be wall-mounted, detachable, or integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected through an intermediate medium, or connected between two elements.
The embodiment provides a method for predicting sinking depth of a collapsed hard shell block under the action of waves, which comprises the following steps:
(1) Determining the thickness z of the crust layer 1 The water depth d.
Drilling at the crust, determining the thickness z of the crust using the drilling result 1 (ii) a And measuring the water depth at the hard shell layer by using a water depth measuring tool, and determining the water depth d at the hard shell layer.
(2) Determination of non-drainage shear strength c of crust soil mass u 。
The undisturbed soil sample taken out by drilling of the crust layer is transported back to a laboratory for a miniature cross plate shear test to determine the non-drainage shear strength c of the crust layer soil body u 。
(3) Determining crustSevere gamma of layer 1 And heavy gamma of lower weak soil 2 。
The original state soil sample which is taken out by drilling the hard shell layer and the soft soil body at the lower part is transported back to a laboratory for density test, after the density is respectively tested, the gravity acceleration is respectively multiplied to obtain the heavy gamma of the hard shell layer 1 And the heavy gamma of the lower weak soil body 2 。
(4) And determining the cohesive force c of the weak soil body under the hard shell layer.
The undisturbed soil sample taken out from the soft soil body at the lower part is transported back to a laboratory for direct shear test, and the cohesive force c of the undisturbed soil sample is tested.
(5) Wave parameters including wave height H, wavelength L at the hard shell at extreme sea conditions are determined.
According to the actual measurement data or theoretical calculation, wave parameters including wave height H and wavelength L of the hard shell layer under extreme sea conditions are determined.
(6) Determining the pressure limit p of the wave against the crust 0 。
Wherein, γ w Taking 10.25kN/m for the seawater gravity 3 。
(7) Determining the average wave pressure p in the collapsed area 1 。
Wherein, B is the side length of the collapsed block and is a parameter to be solved.
(8) And determining the edge length B of the collapsed block.
Solving equation and determining collapsed block edge length B, p 1 B＝4z 1 c u The smaller of the results is taken.
(9) Determining the dead weight G of the collapsed crust.
G＝B 2 z 1 γ 1
(10) And determining the subsidence depth h of the collapsed crust blocks under the action of the waves.
Solving an equation, determining the subsidence depth h,
(B 2 +4Bh)c+γ 2 B 2 h＝B 2 p 1 +G
example of the embodiment
A crust layer is developed on the surface of a seabed of a certain sea area in China, and a plurality of petroleum pipelines are arranged in the sea area, so that the sinking depth of a collapsed block under the action of waves needs to be determined in advance for evaluating the influence of the collapsed block of the crust layer on the petroleum pipelines, and the method is adopted for prediction.
Drilling at the crust and using the drilling result to determine the thickness z of the crust 1 Is 0.66m; and measuring the water depth at the hard shell layer by using a water depth measuring tool, and determining that the water depth d at the hard shell layer is 11.2m. Transporting the undisturbed soil sample taken out by drilling of the hard shell layer back to a laboratory for a miniature cross plate shear test to determine the non-drainage shear strength c of the soil body of the hard shell layer u The pressure was 26.1kPa. The undisturbed soil sample obtained by drilling the crust layer and the lower soft soil body is transported back to a laboratory for density test, and after the density is respectively tested, the density is multiplied by the gravity acceleration respectively to obtain the severe gamma of the crust layer 1 Is 19.3kN/m 3 And heavy gamma of lower weak soil 2 Is 16.1kN/m 3 . An undisturbed soil sample taken out of a soft soil body at the lower part is transported back to a laboratory for direct shear test, and the cohesive force c of the undisturbed soil sample is tested to be 13.6kPa. According to theoretical calculation, wave parameters of the hard shell layer under extreme sea conditions are determined, wherein the wave height H is 4.3m, and the wavelength L is 51.7m. Determining the pressure limit p of the wave against the crust 0 10.6kPa. Determining the average wave pressure p in the collapsed area 1 Is 10.6-0.2B. Further, the collapsed side length B was found to be 7.6m. The dead weight G of the collapsed hard shell is determined to be 733.1kN. And finally, solving an equation to determine that the subsidence depth h of the collapsed block of the hard shell layer is 0.35m under the action of the waves.
The above description is only a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any person skilled in the art can make insubstantial changes in the technical scope of the present invention within the technical scope of the present invention, and the actions infringe the protection scope of the present invention are included in the present invention.
Claims (6)
1. A method for predicting sinking depth of a collapsed hard shell under the action of waves is characterized by comprising the following steps:
(1) Determining the thickness z of the crust layer 1 Depth of water d;
(2) Determination of the non-drainage shear strength c of the crust soil u ；
(3) Determining the severity of the crust 1 And heavy gamma of lower weak soil 2 ；
(4) Determining the cohesive force c of a weak soil body at the lower part of a hard shell layer;
(5) Determining wave parameters including wave height H and wavelength L at the position of a hard shell layer under an extreme sea condition;
(6) Determining the pressure limit p of the wave against the crust 0 ：
Wherein, γ w Taking 10.25kN/m for the seawater gravity 3 ；
(7) Determining the average wave pressure p in the collapsed area 1 ：
B is the side length of the collapsed block, and is a parameter to be solved;
(8) Determining the edge length B of the collapsed block;
solving an equation, and determining collapsed block edge length B, p 1 B＝4z 1 c u Taking the smaller of the results;
(9) Determining the dead weight G of a collapsed block of the hard shell layer;
G＝B 2 z 1 γ 1
(10) Determining the subsidence depth h of the collapsed crust block under the action of waves:
solving an equation, determining the subsidence depth h,
(B 2 +4Bh)c+γ 2 B 2 h＝B 2 p 1 +G。
2. the method for predicting sinking depth of collapsed hard shell under the action of waves as claimed in claim 1, wherein: drilling at the crust in step 1, determining the thickness z of the crust using the drilling result 1 (ii) a And measuring the water depth at the hard shell layer by using a water depth measuring tool to determine the water depth d at the hard shell layer.
3. The method for predicting sinking depth of collapsed hard shell under the action of waves as claimed in claim 1, wherein: step 2, transporting the undisturbed soil sample taken out by drilling of the crust layer back to a laboratory for a miniature cross plate shearing test to determine the non-drainage shearing strength c of the crust layer soil body u 。
4. The method for predicting sinking depth of hard shell collapsed blocks under the action of waves as claimed in claim 1, wherein: in step 3, the undisturbed soil samples which are taken out by drilling the hard shell layer and the lower soft soil body are transported back to a laboratory for density tests, and after the densities are respectively tested, the densities are respectively multiplied by the gravity acceleration to obtain the severe gamma of the hard shell layer 1 And heavy gamma of lower weak soil 2 。
5. The method for predicting sinking depth of hard shell collapsed blocks under the action of waves as claimed in claim 1, wherein: and 4, transporting the undisturbed soil sample taken out from the soft soil body at the lower part back to a laboratory for direct shear test, and testing the cohesive force c of the undisturbed soil sample.
6. The method for predicting sinking depth of collapsed hard shell under the action of waves as claimed in claim 1, wherein: and 5, determining wave parameters including wave height H and wavelength L when the hard shell layer is in an extreme sea state according to actual measurement data or theoretical calculation.
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| CN202211233723.7A CN115618593A (en) | 2022-10-10 | 2022-10-10 | Method for predicting sinking depth of collapsed hard shell under wave action |
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