A wedge measuring device and method suitable for measuring the external soil force of a tubular pile

Abstract

This invention relates to a wedge-shaped measuring device and method for measuring the forces exerted by marine soil on external casing piles. The device includes a sliding wedge and a piezoelectric ceramic sensor fixed to the sliding wedge. The piezoelectric ceramic sensor is communicatively connected to a controller of an offshore operating platform and is used to measure the pressure value of the sliding wedge. Several sliding wedges are evenly distributed along the circumferential direction of the casing pile. This device is used to measure the forces exerted by the remolded marine soil on external casing piles during installation, and then calculates actual marine soil bearing capacity data such as soil weight and at-rest earth pressure coefficient.

Description

Technical Field

[0001] This invention relates to a wedge block measuring device and method for measuring the forces exerted by the soil in the open sea on pipe piles, belonging to the field of marine engineering technology. Background Technology

[0002] Pipeline piles, such as offshore drilling guide pipes and suction piles, rely on the constraint force of the seabed for anchorage. During the installation of these piles, the seabed outside the pile is disturbed, and the anchorage force provided by the remolded seabed is difficult to obtain in engineering practice. Calculating this anchorage force using soil pressure and bearing capacity coefficients obtained from preliminary surveys is inaccurate because it does not account for changes in the bearing capacity of the seabed during pile installation. Currently, there is a lack of an effective method or device to directly measure the remolded bearing capacity of each soil layer encountered during the installation of pipeline piles. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a wedge block measuring device and method for measuring the force of marine soil outside a pipe-tube pile. This device is used to measure the force of remolded marine soil outside the pipe-tube pile during installation, and then calculates and obtains actual marine soil bearing capacity data such as soil weight and static earth pressure coefficient.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A wedge-shaped measuring device for measuring the forces of offshore soil on pipe-tube piles includes: A sliding wedge and a piezoelectric ceramic sensor fixed on the sliding wedge, the piezoelectric ceramic sensor being communicatively connected to the controller of the offshore operating platform for measuring the pressure value of the sliding wedge; The sliding wedges are of several kinds and are evenly distributed in the circumferential direction of the pipe pile.

[0005] A wedge block measurement method for measuring the forces of offshore soil on pipe piles, preferably using the aforementioned wedge block measuring device, specifically includes the following steps: Pipe piles equipped with the wedge measuring device are driven into the seabed. During the pile driving process, the pressure values ​​of the sliding wedges in different soil layers are measured using the piezoelectric ceramic sensor. Then, the static earth pressure coefficients of the soil layers in the elastic and plastic failure stages are calculated based on the pressure values. and soil weight .

[0006] The wedge measurement method, preferably, uses the following formula to calculate the pressure value of the sliding wedge in different soil layers:

[0007] in, In order to be in The pressure value measured by the piezoelectric sensor above the wedge at the depth position; The circumferential stress of the soil; Vertical stress in the soil; exist Coefficient of earth pressure at rest at depth; exist The weight of the soil at depth; The coefficient of friction between the wedge and the cylindrical pile; Angle of attack of the wedge.

[0008] The aforementioned wedge measurement method preferably uses the coefficient of static earth pressure of the soil layer in the elastic stage of the soil mass. and soil weight The calculation formula is as follows:

[0009]

[0010] At the same depth, the above two equations are obtained by measuring wedges at different angles along the circumference of the circular pipe pile. By solving these equations simultaneously, the coefficient of earth pressure at rest at that depth can be calculated. and soil weight .

[0011] The aforementioned wedge measurement method preferably measures the coefficient of at-rest earth pressure in the soil layer during the plastic failure stage of soil displacement. and soil weight The calculation formula is as follows:

[0012] In the formula, the wavy line above each variable indicates the moment when the soil is at yield; The friction coefficient of the inclined surface of the wedge at the ultimate failure point can be considered as a constant. This represents the shear stress on the inclined surface of the wedge at the ultimate failure point. This represents the normal stress on the inclined surface of the wedge at the ultimate failure point. It is the soil cohesion; The friction angle within the soil.

[0013] The present invention has the following advantages due to the adoption of the above technical solutions: The measuring device of the present invention is used to measure the force of the remolded marine soil outside the pipe pile during installation, and then calculate the actual marine soil bearing capacity data such as soil weight and static earth pressure coefficient. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the wedge measuring device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the stress analysis of the wedge and soil element in the elastic stage of soil provided in this embodiment of the invention; Figure 3 This is a schematic diagram of the force analysis of the wedge block provided in this embodiment of the present invention; Figure 4 This is a three-dimensional stress circle diagram of marine soil provided in this embodiment of the present invention; Figure 5 This is a schematic diagram of the force analysis at the yielding moment of the wedge block provided in this embodiment of the invention; Figure 6 This is a schematic diagram of the stress analysis of the soil element at the moment of wedge yielding provided in this embodiment of the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0016] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," "third," "fourth," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0017] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "above," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0018] Pipe piles, such as offshore drilling guide pipes and suction piles, rely on the constraint force of the seabed for anchorage. During the installation of these pipe piles, the seabed outside the pile is disturbed, and the anchoring force provided by the remolded seabed is difficult to obtain in engineering practice. Calculating this anchoring force using the soil bearing capacity coefficient obtained from preliminary surveys is inaccurate because it does not account for changes in the bearing capacity of the seabed during pile installation. Currently, there is a lack of an effective method or device to directly measure the remolded bearing capacity of each soil layer encountered during pipe pile installation.

[0019] Based on the above-mentioned technical problems, the present invention provides a wedge block measuring device suitable for measuring the force of the marine soil outside the pipe pile. This device is used to measure the force of the remolded marine soil outside the pipe pile during installation, and then calculate the actual marine soil bearing capacity data such as soil weight and static earth pressure coefficient.

[0020] like Figure 1 As shown, the wedge measuring device for measuring the force of the offshore soil on the casing pile involved in this invention includes: a sliding wedge and a piezoelectric ceramic sensor fixed on the sliding wedge. The piezoelectric ceramic sensor is communicatively connected to the controller of the offshore operating platform and is used to measure the pressure value of the sliding wedge. The sliding wedges are a number of pieces and are evenly arranged in the circumferential direction of the casing pile.

[0021] like Figure 2 , 3 As shown, the force analysis of the sliding wedge and soil element is as follows: The forces acting on the sliding wedge are as follows:

[0022]

[0023]

[0024] The soil element is subjected to the following forces:

[0025]

[0026]

[0027] In the formula, In order to be in The pressure value measured by the piezoelectric sensor above the wedge at the depth position; This refers to the frictional force between the wedge and the cylindrical wall. This represents the total frictional force on the inclined surface of the wedge. This represents the total pressure on the inclined surface of the wedge. This refers to the compressive force exerted by the wedge on the cylindrical pile. The normal stress is the stress on the surface perpendicular to the inclined plane of the wedge. The normal stress on the inclined surface of the wedge; The circumferential stress of the soil; Vertical stress in the soil; The shear stress on the inclined surface of the wedge; The coefficient of friction between the wedge and the cylindrical pile; Angle of attack of the wedge.

[0028] like Figure 4As shown, it is a three-dimensional stress circle diagram of the marine soil. The pressure value received by the sliding wedge measured by the piezoelectric ceramic sensor is as follows:

[0029] Therefore:

[0030] In the formula, exist Coefficient of earth pressure at rest at depth; exist The weight of the soil at depth.

[0031] The technical solution of the present invention will be described in detail below with reference to specific examples.

[0032] The bearing capacity of the outer wedge block of the pile can be divided into two stages: the elastic deformation stage of the soil and the plastic failure stage of soil displacement.

[0033] ① In the elastic stage of soil, the mutual compression between the wedge and the soil is not obvious, there is no relative slippage between the wedge and the soil, and load changes will not cause normal pressure on the wedge-soil interface. The change in [the force] will only cause frictional shear force. The load is mainly borne by the frictional shear stress between the wedge and the soil. During this stage, the mutual compression between the wedge and the soil is relatively weak; the maximum load is the critical plastic load of the wedge, and the piezoelectric ceramic at the top of the wedge is under pressure. The corresponding pressure value is measured. .

[0034]

[0035]

[0036] At the same depth, along the circumference of the cylindrical pile, wedges at different angles (for simplicity, their inclined surfaces can be made to have the same area, i.e.) The measurements yielded two equations, namely equation (1) and equation (2), which, when combined, can be used to calculate the coefficient of earth pressure at rest at that depth. and soil weight .

[0037] ② As the load continues to increase, the frictional force between the wedge and the soil cannot fully bear the external load. The wedge moves downward, and mutual compression occurs between the wedge and the soil, causing changes in the normal pressure and frictional shear force between them. The wedge and soil then enter the plastic failure stage of soil squeezing. At this point, the increased load is borne by the normal stress and shear stress at the wedge-soil interface until shear failure occurs in the soil at the wedge-soil interface, and the measured value of the piezoelectric ceramic at the top of the wedge reaches its limit.

[0038] like Figure 5As shown, the force analysis and equilibrium equations of the wedge are as follows:

[0039]

[0040]

[0041]

[0042]

[0043] The soil on the inclined surface of the wedge is in a state of shear failure, with the following characteristics:

[0044] There are also limit equilibrium conditions for cohesive soils:

[0045] In the formula, The pressure measured by the piezoelectric ceramic at the ultimate failure point; This represents the shear force on the inclined surface of the wedge at the ultimate failure point. This represents the pressure on the inclined surface of the wedge at the point of ultimate failure. This refers to the circumferential stress of the soil at ultimate failure. This represents the vertical stress of the soil at the point of ultimate failure. The friction coefficient of the inclined surface of the wedge at the ultimate failure point can be considered as a constant. This represents the shear stress on the inclined surface of the wedge at the ultimate failure point. This represents the normal stress on the inclined surface of the wedge at the ultimate failure point. It is the soil cohesion; The friction angle within the soil.

[0046] The stress analysis of the soil element is as follows:

[0047]

[0048]

[0049] In the formula, This is the normal stress on the surface perpendicular to the inclined plane of the wedge at the ultimate failure point.

[0050] From equation (3):

[0051] In the above formula, the superscript wavy line of the variable indicates that the soil is at the yielding moment.

[0052] Substituting equation (4) into equation (5), we get:

[0053] Following the process in ①, using two wedges at different angles, the coefficient of earth pressure at rest at a certain depth at the moment of yielding can be measured. and soil weight .Will and Substituting into equation (6), we can also obtain and Relational expression (7):

[0054] and The relational expression (7) can provide a reference for the design of inclined piles and wedge piles in the local sea area.

[0055] ③ For continuously driven cylindrical piles, the wedges traverse multiple layers of soil, and the measured depths correspond to different depths. The at-rest earth pressure coefficient of each remolded soil layer can be calculated. and soil weight (Two wedges at different angles need to be installed along the circumference of the cylindrical pile.)

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring the wedge block of a tubular pile subjected to external soil forces, the method being based on a wedge block measuring device, the wedge block measuring device comprising: A sliding wedge and a piezoelectric ceramic sensor fixed on the sliding wedge, the piezoelectric ceramic sensor being communicatively connected to the controller of the offshore operating platform and used to measure the pressure value of the sliding wedge; the sliding wedges are of several kinds and are evenly arranged in the circumferential direction of the pipe pile; The method is characterized by using the wedge measuring device for measurement, specifically including the following steps: The pipe pile carrying the wedge measuring device is driven into the seabed, and the piezoelectric ceramic sensor is used to measure the pressure value of the sliding wedge in different soil layers during the driving process, and then the static earth pressure coefficient of the soil layer in the elastic stage and the soil compaction plastic failure stage is calculated according to the pressure value and the soil bulk density ; The formula for calculating the pressure value of the sliding wedge in different soil layers is as follows: ； in, In order to be in The pressure value measured by the piezoelectric sensor above the wedge at the depth position; The circumferential stress of the soil; Vertical stress in the soil; exist Coefficient of earth pressure at rest at depth; exist The weight of the soil at depth; The coefficient of friction between the wedge and the cylindrical pile; Angle of attack of the wedge; S Let be the area of ​​the wedge surface of the wedge block.

2. The wedge measurement method according to claim 1, characterized in that, Coefficient of earth pressure at rest in elastic range of soil and the specific weight of the soil The calculation formula is as follows: ； ； At the same depth, along the circular tube pile ring, the wedge block at different angles is measured to obtain the above two equations, which can be calculated together to calculate the static earth pressure coefficient at this depth and the specific gravity of the soil , S 1、 S 2 is the wedge surface area of the wedge block at different slope toe 3. The wedge measurement method according to claim 2, characterized in that, The static earth pressure coefficient of each soil layer is successively plastically destroyed when the cylindrical pile is continuously pressed and the specific weight of the soil The calculation formula is as follows: ； In the formula, each variable superscript tilde represents the moment when the soil is in yield; is the friction coefficient of the wedge inclined surface at the limit failure time, which can be regarded as a constant value; is the shear stress of the wedge inclined surface at the limit failure time; is the normal stress of the wedge inclined surface at the limit failure time; is the cohesion of the soil; is the internal friction angle of the soil.

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