Method for determining the construction window period of offshore trestle under the coupling of wind, waves and current

Abstract

The present invention discloses a method for determining the construction window period of an offshore construction trestle under the coupling of wind, wave and current, comprising: constructing a vibration analysis model of the offshore construction trestle to generate a three-dimensional random wind field and a random wave-current coupling field; establishing a vibration equation of the offshore construction trestle under the coupling of wind, wave and current; solving the vibration equation to obtain the vibration acceleration of the deck of the offshore construction trestle, and then obtaining the vibration comfort of the workers on the offshore construction trestle; judging whether the vibration comfort of the workers on the offshore construction trestle within a certain continuous time period is less than or equal to a preset allowable comfort limit for the workers on the offshore construction trestle, and if so, taking the continuous time period as the construction window period of the offshore construction trestle. The present invention uses the comfort of the workers on the offshore construction trestle as a criterion for judging, and can accurately determine the construction window period of the offshore construction trestle under the coupling of wind, wave and current, thereby improving the safety and comfort of the workers on the offshore construction trestle.

Description

Technical Field

[0001] The present disclosure relates to the technical field of disaster prevention and mitigation of bridge engineering, and in particular to a method for determining a construction window period of an offshore trestle under the coupling of wind, wave and current. Background Art

[0002] Offshore construction trestles are commonly used material transportation channels in cross-sea bridge projects, and are also working platforms for personnel and machinery. Offshore construction trestles were used in the construction of cross-sea bridges such as the Pingtan Strait Highway-Rail Bridge and the China-Malaysia Friendship Cross-Sea Bridge.

[0003] Offshore construction trestles require significant investment and high economic efficiency. Their importance also demands high safety in complex and changing environments throughout their service life. Currently, no technical specifications for offshore construction trestles have been established domestically or internationally. Without these standards, ensuring both safety and economic efficiency in marine environments presents a significant challenge for trestle designers. Key technical challenges in offshore trestle construction include determining design and construction standards, and evaluating their safety and comfort.

[0004] In an ocean environment, with strong winds, high waves, and rapid currents, offshore construction trestle bridges are subject to the coupling effects of wind, waves, and currents. Under adverse weather conditions, offshore construction trestle bridges can experience significant vibrations due to this interaction, causing discomfort to bridge owners and personnel, impacting the safety and comfort of construction operations. Therefore, to ensure the safety and comfort of workers on offshore construction trestle bridges, it is necessary to ensure that they operate safely within a certain construction window. Summary of the Invention

[0005] (1) Technical issues to be resolved

[0006] In view of this, the main purpose of the present disclosure is to provide a method for determining the construction window period of an offshore construction trestle under the coupling of wind, wave and current, so as to accurately determine the construction window period of an offshore construction trestle under the coupling of wind, wave and current, and improve the safety and comfort of workers on the offshore construction trestle.

[0007] (2) Technical solution

[0008] To achieve the above objectives, the present disclosure provides a method for determining a construction window period for an offshore trestle under the coupled effects of wind, waves and currents, comprising:

[0009] A vibration analysis model of the offshore construction trestle 1 is constructed based on the geometric, physical, and boundary characteristic parameters of the offshore construction trestle, and a three-dimensional random wind field and a random wave-current coupling field are generated based on the marine environmental parameters acting on the offshore construction trestle 1, wherein the marine environmental parameters include at least wind 2, wave 3, and current 4;

[0010] Based on the constructed vibration analysis model and the generated three-dimensional random wind field and random wave-current coupling field, a vibration equation of the offshore construction trestle 1 under the wind-wave-current coupling effect is established;

[0011] Solving the vibration equation of the offshore construction trestle 1 under the coupling of wind, waves and current to obtain the vibration acceleration of the deck of the offshore construction trestle 1, and obtaining the vibration comfort of the workers 5 on the offshore construction trestle 1 based on the vibration acceleration of the deck of the offshore construction trestle 1; and

[0012] It is determined whether the vibration comfort level of the workers 5 on the offshore construction trestle 1 within a certain continuous time period is less than or equal to a preset allowable comfort level limit for the workers 5 on the offshore construction trestle 1. If yes, the continuous time period is used as a construction window period for the offshore construction trestle 1.

[0013] In the above scheme, in the step of establishing the vibration equation of the offshore construction trestle (1) under the wind-wave-current coupling action based on the constructed vibration analysis model and the generated three-dimensional random wind field and random wave-current coupling field,

[0014] The sub-water piles 6 of the offshore construction trestle 1 are subjected to the combined effects of waves 3 and ocean currents 4;

[0015] The piles 7 above the water surface of the offshore construction trestle 1 are subjected to the action of the wind 2; and

[0016] The main beam 8 of the offshore construction trestle 1 is subjected to the action of the wind 2 per unit length.

[0017] In the above solution, the sub-water piles 6 of the offshore construction trestle 1 are subjected to the combined effects of waves 3 and currents 4, specifically using the following formula:

[0018]

[0019] in, is the wave and current force on the pile 6 unit length below the water surface; C D is the velocity force coefficient; ρ w is the density of seawater; D1 is the diameter of the pile 6 below the water surface; v w and a w is the water particle velocity and acceleration, is the effective wave height H in the engineering sea area w , average period T w , wave propagation direction α w and the function of ocean current velocity v0; C A is the additional inertia coefficient; A p is the cross-sectional area of ​​pile 6 below the water surface.

[0020] In the above scheme, the piles 7 above the water surface of the offshore construction trestle 1 are affected by the wind 2, specifically using the following formula:

[0021]

[0022] in, is the wind load on pile 7 above the water surface; ρ is the air density; U p and u p is the average wind speed and horizontal fluctuating wind speed related to pile 7 above the water surface, and the ten-minute average wind speed U at a height of 10 meters at the bridge position 10 Related; D2 is the diameter of the pile 7 above the water surface; C C is the drag coefficient of pile 7 above the water surface.

[0023] In the above solution, the main beam 8 of the offshore construction trestle 1 is subjected to the action of wind 2 per unit length, specifically using the following formula:

[0024]

[0025]

[0026]

[0027] Among them, f bH 、f bV and f bM is the resistance, lift and lift moment per unit length of the main beam 8; ρ is the air density; U b 、u b and w b The average wind speed, horizontal and vertical pulsating wind speed components at the center of the main beam 8 and the ten-minute average wind speed U at a height of 10 meters at the bridge position are 10 Related; H is the characteristic height of the main beam 8; C H 、C V and C M is the drag coefficient, lift coefficient and torque coefficient of the main beam 8; B is the characteristic width of the main beam 8; C' H , C′ V and C′ M It is the derivative of the drag coefficient, lift coefficient and lift moment coefficient of the main beam 8.

[0028] In the above solution, the vibration equation of the offshore construction trestle 1 under the coupling of wind, wave and current is specifically formulated as follows:

[0029]

[0030] Wherein, M, C and K represent the mass, damping and stiffness matrices of the offshore construction trestle 1 respectively; X, and represent the displacement, velocity and acceleration of the offshore construction trestle 1 respectively; The column vector of wave and current loads on the pile 6 under the water surface of the offshore construction trestle 1 is calculated by And transformed into; The column vector of wind load on the pile 7 above the water surface of the offshore construction trestle 1 is calculated by And transformed into; F B To represent the column vector of wind load on the main beam 8 of the offshore construction trestle 1, we calculate f bH 、f bV and f bM And converted.

[0031] In the above scheme, the vibration equation of the offshore construction trestle 1 under the coupling of wind, wave and current is solved to obtain the vibration acceleration of the bridge deck of the offshore construction trestle 1, and the vibration comfort of the workers 5 on the offshore construction trestle 1 is obtained according to the vibration acceleration of the bridge deck of the offshore construction trestle 1, including: the vibration acceleration a(t) of the bridge deck of the offshore construction trestle 1 is obtained by solving formula 6, and then the vibration acceleration a(t) of the bridge deck of the offshore construction trestle 1 is converted into the overall weighted acceleration A of the bridge deck of the offshore construction trestle 1 w , the overall weighted acceleration A w The maximum overall weighted acceleration max(A w ) as the vibration comfort of the workers 5 on the offshore construction pier 1.

[0032] In the above scheme, the vibration acceleration a(t) of the deck of the offshore construction trestle 1 is converted into the overall weighted acceleration A of the deck of the offshore construction trestle 1. w , specifically including:

[0033] Calculate the power spectrum density function G of the deck vibration acceleration a(t) of the offshore construction trestle 1 a (f), the power spectral density function G a (f) Multiply by the square of the frequency weighting function and integrate in the range of 1 to 80 Hz to obtain the weighted acceleration a w for

[0034]

[0035] Where W(f) is the frequency weighting function;

[0036] For horizontal vibration

[0037]

[0038] For vertical vibration

[0039]

[0040] Calculate the weighted acceleration a of horizontal vibration and vertical vibration according to equations 7 to 9 respectively wx , a wy , a wz , and then use formula 10 to get the overall weighted acceleration A w

[0041] A w =[(1.4a wx ) 2 +(1.4a wy ) 2 +(a wz ) 2 ] 1 / 2 Formula 10.

[0042] In the above scheme, in the step of judging whether the vibration comfort of the workers 5 on the offshore construction trestle 1 in a certain continuous time period is less than or equal to the preset allowable comfort limit of the workers 5 on the offshore construction trestle 1, the preset allowable vibration comfort limit of the workers 5 on the offshore construction trestle 1 is A, wherein A is between 0.315 and 1.0, and the specific value is determined by the construction party based on the balance between construction safety and construction period. The smaller A is, the lower the construction safety of the workers but the shorter the construction period, and the larger A is, the higher the construction safety of the workers but the longer the construction period; if the vibration comfort of the workers 5 on the offshore construction trestle 1 in a certain continuous time period is less than or equal to A, that is, max(A w )≤A, then the continuous time period is regarded as the construction window period of the offshore construction trestle 1; if the vibration comfort level of the operator 5 on the offshore construction trestle 1 is greater than A in a certain continuous time period, that is, max(A w )>A, then this continuous time period cannot be used as the construction window period of the offshore construction trestle 1.

[0043] In the above scheme, when the structure of the offshore construction trestle 1 is determined, the vibration comfort level A of the workers 5 on the offshore construction trestle 1 within a certain continuous time period is p The water level h and the average wind speed U at 10 meters above the bridge for ten minutes are 10 , significant wave height H in engineering sea area w , wave average period T w , wave propagation direction α w It is determined by environmental parameters such as the ocean current velocity v0 and can be expressed using Formula 11 as follows:

[0044] A p =f(h,U 10 , H w , T w , α w , v0) Formula 11

[0045] When the comfort level A of the operator 5 on the offshore construction trestle 1 is affected by the coupling of wind, wave and current in a certain continuous time period, p When formula 12 is satisfied, the continuous time period is used as the construction window period of the offshore construction trestle 1;

[0046] A p =f(h,U 10 , H w , T w , α w , v0)<A Formula 12.

[0047] (3) Beneficial effects

[0048] It can be seen from the above technical solutions that the method for determining the construction window period of an offshore trestle under the coupling of wind, wave and current provided by the present disclosure has the following beneficial effects:

[0049] 1. The present disclosure provides a method for determining a construction window period for an offshore construction trestle under the coupled effects of wind, wave, and current. By comprehensively considering the combined effects of wind, wave, and current on the offshore construction trestle, a vibration equation for the offshore construction trestle under the coupled effects of wind, wave, and current is established. The vibration acceleration of the deck of the offshore construction trestle 1 is obtained by solving the vibration equation, and further the vibration comfort of the workers 5 on the offshore construction trestle 1 is obtained. When the vibration comfort of the workers 5 on the offshore construction trestle 1 during a certain continuous time period is less than or equal to a preset allowable comfort limit for the workers 5 on the offshore construction trestle 1, the continuous time period is used as the construction window period for the offshore construction trestle 1. This method can accurately determine the construction window period for the offshore construction trestle under the coupled effects of wind, wave, and current, thereby improving the safety and comfort of the workers on the offshore construction trestle.

[0050] 2. The method for determining the construction window period of an offshore construction trestle under the coupling effect of wind, wave and current provided in the present disclosure provides scientific and reasonable guidance for determining the construction window period of an offshore construction trestle under the coupling effect of wind, wave and current.

[0051] 3. The method for determining the construction window period of an offshore construction trestle under the coupled effects of wind, waves and currents provided by the present disclosure uses the comfort level of workers on the construction trestle as a basis for evaluating whether normal construction can be carried out, making the process of selecting and deciding the construction window period more quantitative and operational. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of the force analysis of an offshore construction trestle under the coupling of wind, waves and currents provided by the present disclosure;

[0053] Figure 2 A flow chart of a method for determining a construction window period for an offshore trestle under the coupling of wind, waves and currents provided by the present disclosure;

[0054] Figure 3 Schematic diagram of the correlation between main marine environmental parameters, operator comfort, and construction window period of an offshore construction pier according to an embodiment of the present disclosure.

[0055] Figure numerals: 1 - offshore construction trestle; 2 - wind; 3 - waves; 4 - ocean current; 5 - workers; 6 - piles below the water surface; 7 - piles above the water surface; 8 - main beam. DETAILED DESCRIPTION

[0056] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0057] Reference Figure 1 and Figure 2 The present disclosure provides a method for determining a construction window period of an offshore trestle under the coupled effects of wind, wave and current, the method comprising the following steps:

[0058] Step 1: Construct a vibration analysis model of the offshore construction trestle 1 based on the geometric, physical, and boundary characteristic parameters of the offshore construction trestle, and generate a three-dimensional random wind field and a random wave-current coupling field based on the marine environmental parameters acting on the offshore construction trestle 1; wherein the marine environmental parameters include at least wind 2, wave 3, and current 4;

[0059] Step 2: Based on the constructed vibration analysis model and the generated three-dimensional random wind field and random wave-current coupling field, a vibration equation of the offshore construction trestle 1 under the wind-wave-current coupling effect is established;

[0060] Step 3: Solve the vibration equation of the offshore construction trestle 1 under the coupled effects of wind, waves and current to obtain the vibration acceleration of the deck of the offshore construction trestle 1 , and obtain the vibration comfort of the workers 5 on the offshore construction trestle 1 based on the vibration acceleration of the deck of the offshore construction trestle 1 ;

[0061] Step 4: Determine whether the vibration comfort level of the workers 5 on the offshore construction trestle 1 during a certain continuous time period is less than or equal to a preset allowable comfort level limit for the workers 5 on the offshore construction trestle 1. If yes, use the continuous time period as the construction window period for the offshore construction trestle 1.

[0062] In the embodiment of the present disclosure, the step 1 of constructing the vibration analysis model of the offshore construction trestle 1 according to the geometric, physical and boundary characteristic parameters of the offshore construction trestle is based on the geometric, physical and boundary characteristic parameters of the construction trestle such as piles and main beams, and the vibration analysis model of the offshore construction trestle 1 is constructed using the finite element method.

[0063] In the embodiment of the present disclosure, the ocean environment parameters described in step 1 include at least wind 2, waves 3 and current 4. Specifically, the ocean environment parameters can be water level, wave height, wave period, wave direction, wind speed, current speed, etc. within a certain time period.

[0064] In the embodiment of the present disclosure, step 2 establishes a vibration equation of the offshore construction trestle 1 under the action of wind-wave-current coupling based on the constructed vibration analysis model and the generated three-dimensional random wind field and random wave-current coupling field, wherein the piles 6 below the water surface of the offshore construction trestle 1 are affected by the combined action of waves 3 and ocean currents 4, the piles 7 above the water surface of the offshore construction trestle 1 are affected by wind 2, and the main beam 8 of the offshore construction trestle 1 is affected by wind 2 per unit length.

[0065] According to the embodiment of the present disclosure, the submerged piles 6 of the offshore construction trestle 1 are subjected to the combined effects of waves 3 and currents 4, specifically using the following formula:

[0066]

[0067] in, is the wave and current force on the pile 6 unit length below the water surface; C D is the velocity force coefficient; ρ w is the density of seawater; D1 is the diameter of the pile 6 below the water surface; v w and a w is the water particle velocity and acceleration, is the effective wave height H in the engineering sea area w , average period T w , wave propagation direction α w and the function of ocean current velocity v0; C A is the additional inertia coefficient; A p is the cross-sectional area of ​​pile 6 below the water surface.

[0068] Water particle velocity v w and acceleration a w The random wave theory can be used for calculation:

[0069]

[0070]

[0071]

[0072] ω i =ω i-1 +Δω

[0073] Among them, S ηη is the wave spectrum, which can generally adopt the improved JONSWAP spectrum; M is the number of spectral lines; ε iis a random phase angle that satisfies uniform distribution in the range of [0, 2π]; is the i-th representative frequency; ω i is the i-th frequency; Δω is the frequency increment; For The corresponding wave number can be obtained by using the dispersion equation Calculation; x, y and z are the horizontal and vertical coordinates corresponding to the calculated position of the underwater pile; d is the water depth.

[0074] The improved JONSWAP spectrum expression is:

[0075]

[0076]

[0077]

[0078]

[0079] Where, ω m is the spectrum peak frequency; γ is the spectrum peak raising factor, which can generally be taken as 3.3.

[0080] According to the embodiment of the present disclosure, the piles 7 above the water surface of the offshore construction trestle 1 are subjected to the action of the wind 2, specifically using the following formula:

[0081]

[0082] in, is the wind load on pile 7 above the water surface; ρ is the air density; U p and u p is the average wind speed and horizontal fluctuating wind speed related to pile 7 above the water surface, and the ten-minute average wind speed U at a height of 10 meters at the bridge position 10 Related; D2 is the diameter of the pile 7 above the water surface; C C is the drag coefficient of pile 7 above the water surface.

[0083] According to an embodiment of the present disclosure, the main beam 8 of the offshore construction trestle 1 is subjected to the action of wind 2 per unit length, specifically using the following formula:

[0084]

[0085]

[0086]

[0087] Among them, f bH 、f bV and f bMis the resistance, lift and lift moment per unit length of the main beam 8; ρ is the air density; U b 、u b and w b The average wind speed, horizontal and vertical pulsating wind speed components at the center of the main beam 8 and the ten-minute average wind speed U at a height of 10 meters at the bridge position are 10 Related; H is the characteristic height of the main beam 8; C H 、C V and C M is the drag coefficient, lift coefficient and torque coefficient of the main beam 8; B is the characteristic width of the main beam 8; C' H , C′ V and C′ M It is the derivative of the drag coefficient, lift coefficient and lift moment coefficient of the main beam 8.

[0088] The horizontal and vertical fluctuating wind speeds can be assumed to be a stationary random process with a mean of zero, and can be obtained using the harmonic synthesis method, that is, the fluctuating wind speed at a point j in space can be calculated using the following formula:

[0089]

[0090]

[0091] H(ω)[H(ω)] T =S(ω)

[0092] S(ω)=[S ij (ω)]

[0093]

[0094] Where N is the number of spectral lines; Δω=ω up / N is the frequency increment; ω up Upper cutoff frequency; is a random phase angle uniformly distributed in the range [0, 2π]; ω ml is the double subscript frequency; H(ω) is the Cholesky decomposition of the matrix S(ω), H jm (ω) is the element of the matrix H(ω); S i (ω) is the wind spectrum corresponding to the spatial point i; Coh(Δ ij ,ω) is the correlation function between points i and j; Δ ij is the distance from point i to j; θ jm (ω) is H jm The complex angle of (ω).

[0095] The wind spectrum should be obtained by fitting the wind field observation data in the project area. When there is a lack of on-site observation data, the horizontal and vertical wind spectra of the pulsating wind are calculated according to the following formulas:

[0096]

[0097]

[0098]

[0099]

[0100] Among them, S u (n) is the horizontal downwind wind spectrum of the pulsating wind; S w (n) is the vertical wind spectrum of the pulsating wind; n is the pulsation frequency of the wind; u * is the air flow friction velocity; K is a dimensionless constant; z is the height above the water surface; V(Z) is the average wind speed at height Z; is the average height of surrounding buildings; z0 is the rough ground height.

[0101] In the embodiment of the present disclosure, the vibration equation of the offshore construction trestle 1 under the wind-wave-current coupling in step 2 is specifically formulated as follows:

[0102]

[0103] Wherein, M, C and K represent the mass, damping and stiffness matrices of the offshore construction trestle 1 respectively; X, and represent the displacement, velocity and acceleration of the offshore construction trestle 1 respectively; The column vector of wave and current loads on the pile 6 under the water surface of the offshore construction trestle 1 is calculated by And transformed into; The column vector of wind load on the pile 7 above the water surface of the offshore construction trestle 1 is calculated by And transformed into; F B To represent the column vector of wind load on the main beam 8 of the offshore construction trestle 1, we calculate f bH 、f bV and f bM And converted.

[0104] In the embodiment of the present disclosure, the vibration equation of the offshore construction trestle 1 under the coupling of wind, wave and current is solved in step 3 to obtain the vibration acceleration of the bridge deck of the offshore construction trestle 1, and the vibration comfort of the operator 5 on the offshore construction trestle 1 is obtained according to the vibration acceleration of the bridge deck of the offshore construction trestle 1, including: the vibration acceleration a(t) of the bridge deck of the offshore construction trestle 1 is obtained by solving formula 6, and then the vibration acceleration a(t) of the bridge deck of the offshore construction trestle 1 is converted into the overall weighted acceleration A of the bridge deck of the offshore construction trestle 1 w , the overall weighted acceleration A wThe maximum overall weighted acceleration max(A w ) as the vibration comfort of the workers 5 on the offshore construction pier 1.

[0105] According to the embodiment of the present disclosure, the bridge deck vibration acceleration a(t) of the offshore construction trestle 1 is converted into the overall weighted acceleration A of the bridge deck of the offshore construction trestle 1. w , specifically including: calculating the power spectrum density function G of the bridge deck vibration acceleration a(t) of the offshore construction trestle 1 a (f), the power spectral density function G a (f) Multiply by the square of the frequency weighting function and integrate in the range of 1 to 80 Hz to obtain the weighted acceleration a w for

[0106]

[0107] Where W(f) is the frequency weighting function;

[0108] For horizontal vibration

[0109]

[0110] For vertical vibration

[0111]

[0112] Calculate the weighted acceleration a of horizontal vibration and vertical vibration according to equations 7 to 9 respectively wx , a wy , a wz , and then use formula 10 to get the overall weighted acceleration A w

[0113] A w =[(1.4a wx ) 2 +(1.4a wy ) 2 +(a wz ) 2 ] 1 / 2 Formula 10

[0114] In the embodiment of the present disclosure, the step 4 is to determine whether the vibration comfort of the workers 5 on the offshore construction trestle 1 in a certain continuous time period is less than or equal to the preset allowable comfort limit of the workers 5 on the offshore construction trestle 1. The preset allowable vibration comfort limit of the workers 5 on the offshore construction trestle 1 is A, where A is between 0.315 and 1.0. The specific value is determined by the construction party based on the balance between construction safety and construction period. The smaller A is, the lower the construction safety of the workers but the shorter the construction period. The larger A is, the higher the construction safety of the workers but the longer the construction period. If the vibration comfort of the workers 5 on the offshore construction trestle 1 in a certain continuous time period is less than or equal to A, that is, max(A w )≤A, then the continuous time period is regarded as the construction window period of the offshore construction trestle 1; if the vibration comfort level of the operator 5 on the offshore construction trestle 1 is greater than A in a certain continuous time period, that is, max(A w )>A, the operator 5 will feel uncomfortable when working continuously on the offshore construction trestle 1, and this continuous time period cannot be used as the construction window period of the offshore construction trestle 1.

[0115] According to the embodiment of the present disclosure, when the structure of the offshore construction trestle 1 is determined, the vibration comfort level A of the operator 5 on the offshore construction trestle 1 within a certain continuous time period is p The water level h and the average wind speed U at 10 meters above the bridge for ten minutes are 10 , significant wave height H in engineering sea area w , wave average period T w , wave propagation direction α w It is determined by environmental parameters such as the ocean current velocity v0 and can be expressed using Formula 11 as follows:

[0116] A p =f(h,U 10 , H w , T w , α w , v0) Formula 11 When the comfort level A of the operator 5 on the offshore construction trestle 1 is affected by the coupling of wind, wave and current in a certain continuous time period, p When formula 12 is satisfied, the continuous time period is used as the construction window period of the offshore construction trestle 1;

[0117] A p =f(h,U 10 , H w , T w , α w , v0)<A Formula 12.

[0118] like Figure 3 As shown, Figure 3This is a schematic diagram of the correlation between the main marine environmental parameters, operator comfort, and construction window period of the offshore construction trestle according to an embodiment of the present disclosure. In the figure, it is assumed that the preset vibration comfort limit value A = 0.5, the water level h for a certain continuous time period, and the ten-minute average wind speed U at a height of 10 meters at the bridge position are obtained through the meteorological and hydrological forecast system. 10 , significant wave height H in engineering sea area w , wave average period T w , wave propagation direction α w , ocean current velocity v0 and other environmental parameters, the comfort results of the workers 5 on the offshore construction pier 1 during the continuous period can be obtained.

[0119] Figure 3 From 8:00 to 10:00 on June 24, the water level h was 2.0m, and the average wind speed for ten minutes was U at a height of 10 meters at the bridge. 10 The effective wave height in the engineering sea area is 10m / s. w is 4.0m, and the average wave period is T w is 5.0s, wave propagation direction α w The angle of the angle is 60°, the ocean current velocity v0 is 2.0 m / s, and the calculated comfort level is 0.2, which is less than the preset comfort level limit of 0.5 allowed for the workers 5 on the offshore construction pier 1, and can meet the comfort level requirements. Therefore, June 24, 8:00 to 10:00 is the construction window for normal construction.

[0120] Similarly, Figure 3 From 12:00 to 18:00 on June 25, the comfort levels in each two-hour period were calculated to be 0.45, 0.45 and 0.4 respectively, all of which were less than the preset comfort limit of 0.5, and this was also the construction window period for normal construction. From 14:00 to 20:00 on June 24, the comfort levels in each two-hour period were calculated to be 0.55, 0.95 and 0.75 respectively, all of which were greater than the preset comfort limit of 0.5. In order to ensure the safety of the 5 construction workers on the construction trestle, construction should be prohibited.

[0121] According to an embodiment of the present disclosure, if the vibration comfort level of the workers 5 on the offshore construction trestle 1 within a certain continuous time period is greater than a preset allowable comfort level limit for the workers 5 on the offshore construction trestle 1, resulting in the continuous time period being unable to serve as a construction window period for the offshore construction trestle 1, the marine environmental parameters may be further adjusted, such as adjusting the water level, wave height, wave period, wave direction, wind speed, current speed, etc. within a certain time period. The three-dimensional random wind field and random wave-current coupling field are regenerated based on the adjusted marine environmental parameters, and the vibration equation of the offshore construction trestle 1 under the action of wind-wave-current coupling is re-established. After solving the vibration equation, the vibration comfort level of the workers 5 on the offshore construction trestle 1 is re-obtained.

[0122] So far, the method for determining the construction window period of an offshore trestle under the wind-wave-current coupling provided by the present disclosure has been described in detail.

[0123] The present disclosure provides a method for determining a construction window period for an offshore construction trestle under the coupled effects of wind, wave and current. By comprehensively considering the combined effects of wind, wave and current on the offshore construction trestle, a vibration equation for the offshore construction trestle under the coupled effects of wind, wave and current is established. The vibration acceleration of the deck of the offshore construction trestle 1 is obtained by solving the vibration equation, and then the vibration comfort of the workers 5 on the offshore construction trestle 1 is obtained. When the vibration comfort of the workers 5 on the offshore construction trestle 1 within a certain continuous time period is less than or equal to a preset allowable comfort limit for the workers 5 on the offshore construction trestle 1, the continuous time period is used as the construction window period for the offshore construction trestle 1. This method can accurately determine the construction window period for the offshore construction trestle under the coupled effects of wind, wave and current, thereby improving the safety and comfort of the workers on the offshore construction trestle.

[0124] Furthermore, the method for determining the construction window period of an offshore construction trestle under the coupling of wind, wave and current provided by the present disclosure provides scientific and reasonable guidance for determining the construction window period of an offshore construction trestle under the coupling of wind, wave and current. In addition, the present disclosure uses the comfort level of workers on the construction trestle as a basis for evaluating whether normal construction can be carried out, making the process of construction window selection and decision-making more quantitative and operational.

[0125] It should be noted that any implementations not shown or described in the drawings or the main text of the specification are known to those skilled in the art and are not described in detail. Furthermore, the definitions of the components described above are not limited to the specific structures, shapes, or methods described in the embodiments, and can be easily modified or replaced by those skilled in the art.

[0126] Of course, according to actual needs, the present invention may also include other parts, which are irrelevant to the innovation of the present invention and will not be described here.

[0127] Similarly, it should be understood that in order to streamline the present invention and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this method of invention should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments of the preceding invention. Accordingly, the claims that follow the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0128] In addition, in the drawings or descriptions of the specification, similar or identical parts use the same figure numbers. The technical features in the various embodiments exemplified in the specification can be freely combined to form new solutions without conflict. In addition, each claim can be used as an embodiment alone or the technical features in each claim can be combined as a new embodiment. In the drawings, the shape or thickness of the embodiment can be expanded and simplified or conveniently marked. Furthermore, the elements or implementations not shown or described in the drawings are forms known to ordinary technicians in the relevant technical field. In addition, although this article may provide examples of parameters containing specific values, it should be understood that the parameters do not need to be exactly equal to the corresponding values, but can be approximated to the corresponding values ​​within an acceptable error tolerance or design constraint.

[0129] Unless there are technical obstacles or contradictions, the above-mentioned various embodiments of the present invention can be freely combined to form other embodiments, and these other embodiments are all within the protection scope of the present invention.

[0130] Although the present invention is described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to illustrate preferred embodiments of the present invention and are not to be construed as limiting the present invention. The dimensions and proportions in the drawings are merely illustrative and are not to be construed as limiting the present invention.

[0131] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined in the claims and their equivalents.

[0132] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are 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 determining the construction window period of an offshore trestle under the coupling of wind, wave and current, characterized in that: include: A vibration analysis model of an offshore construction trestle (1) is constructed based on the geometric, physical and boundary characteristic parameters of the offshore construction trestle, and a three-dimensional random wind field and a random wave-current coupling field are generated based on the ocean environment parameters acting on the offshore construction trestle (1); the ocean environment parameters at least include wind (2), waves (3) and ocean current (4); Based on the constructed vibration analysis model and the generated three-dimensional random wind field and random wave-current coupling field, a vibration equation of the offshore construction trestle (1) under the wind-wave-current coupling effect is established; Solving the vibration equation of the offshore construction trestle (1) under the coupling of wind, wave and current to obtain the deck vibration acceleration of the offshore construction trestle (1), and obtaining the vibration comfort of the workers (5) on the offshore construction trestle (1) based on the deck vibration acceleration of the offshore construction trestle (1); and Determining whether the vibration comfort level of the operator (5) on the offshore construction trestle (1) during a certain continuous time period is less than or equal to a preset allowable comfort level limit for the operator (5) on the offshore construction trestle (1); if so, determining the continuous time period as a construction window period for the offshore construction trestle (1); Among them, in the step of establishing the vibration equation of the offshore construction trestle (1) under the wind-wave-current coupling effect based on the constructed vibration analysis model and the generated three-dimensional random wind field and random wave-current coupling field, The submerged piles (6) of the offshore construction trestle (1) are subjected to the combined effects of waves (3) and ocean currents (4); The piles (7) above the water surface of the offshore construction trestle (1) are subjected to the action of wind (2); The main beam (8) of the offshore construction trestle (1) is subjected to the action of wind (2) per unit length; The piles (6) below the water surface of the offshore construction trestle (1) are subjected to the combined effects of waves (3) and ocean currents (4), specifically using the following formula: in, is the wave and current force per unit length of the pile (6) below the water surface; C D is the velocity force coefficient; ρ w is the density of seawater; D1 is the diameter of the pile (6) below the water surface; v w and a w is the water particle velocity and acceleration, is the effective wave height H in the engineering sea area w , average period T w , wave propagation direction α w and the function of ocean current velocity v0; C A is the additional inertia coefficient; A p is the cross-sectional area of ​​the pile (6) below the water surface; The piles (7) above the water surface of the offshore construction trestle (1) are subjected to the action of wind (2), specifically using the following formula: in, is the wind load on the pile (7) above the water surface; ρ is the air density; U p and u p is the average wind speed and horizontal fluctuating wind speed related to the pile (7) above the water surface, and the ten-minute average wind speed U at a height of 10 meters at the bridge position 10 Related; D2 is the diameter of the pile (7) above the water surface; C C is the drag coefficient of the pile (7) above the water surface; The main beam (8) of the offshore construction trestle (1) is subjected to the action of wind (2) per unit length, specifically using the following formula: Among them, f bH 、f bV and f bM are the resistance, lift and lift moment per unit length of the main beam (8); ρ is the air density; U b 、u b and w b The average wind speed, horizontal and vertical pulsating wind speed components at the center of the main beam (8) and the ten-minute average wind speed U at a height of 10 meters at the bridge position are 10 Related; H is the characteristic height of the main beam (8); C H 、C V and C M is the drag coefficient, lift coefficient and torque coefficient of the main beam (8); B is the characteristic width of the main beam (8); C' H , C' V and C' M It is the derivative of the drag coefficient, lift coefficient and lift moment coefficient of the main beam (8).

2. The method for determining the construction window period of an offshore trestle under the wind-wave-current coupling effect according to claim 1 is characterized in that: The vibration equation of the offshore construction trestle (1) under the coupling effect of wind, wave and current is specifically formulated as follows: Where, M, C and K represent the mass, damping and stiffness matrices of the offshore construction trestle (1) respectively; X, and denote the displacement, velocity and acceleration of the offshore construction trestle (1) respectively; It represents the column vector of wave and current load on the pile (6) below the water surface of the offshore construction trestle (1). And transformed into; The column vector of wind load on the pile (7) above the water surface of the offshore construction trestle (1) is calculated by And transformed into; F B To represent the column vector of wind load on the main beam (8) of the offshore construction trestle (1), we calculate f bH 、f bV and f bM And converted.

3. The method for determining the construction window period of an offshore trestle under the wind-wave-current coupling effect according to claim 2 is characterized in that: The vibration equation of the offshore construction trestle (1) under the coupling of wind, wave and current is solved to obtain the bridge deck vibration acceleration of the offshore construction trestle (1), and the vibration comfort of the workers (5) on the offshore construction trestle (1) is obtained based on the bridge deck vibration acceleration of the offshore construction trestle (1), including: The deck vibration acceleration a(t) of the offshore construction trestle (1) is obtained by solving formula 6, and then the deck vibration acceleration a(t) of the offshore construction trestle (1) is converted into the overall weighted acceleration A of the deck of the offshore construction trestle (1) w , the overall weighted acceleration A w The maximum overall weighted acceleration max(A w ) as the vibration comfort of workers (5) on an offshore construction pier (1).

4. The method for determining the construction window period of an offshore trestle under the wind-wave-current coupling effect according to claim 3 is characterized in that: The bridge deck vibration acceleration a(t) of the offshore construction trestle (1) is converted into the overall weighted acceleration A of the bridge deck of the offshore construction trestle (1) w , specifically including: Calculate the power spectrum density function G of the deck vibration acceleration a(t) of the offshore construction trestle (1) a (f), the power spectral density function G a (f) Multiply by the square of the frequency weighting function and integrate in the range of 1 to 80 Hz to obtain the weighted acceleration a w for Where W(f) is the frequency weighting function; For horizontal vibration For vertical vibration Calculate the weighted acceleration a of horizontal vibration and vertical vibration according to equations 7 to 9 respectively wx , a wy , a wz , and then use formula 10 to get the overall weighted acceleration A w A w = [(1.4a wx ) 2 +(1.4a wy ) 2 +(a wz ) 2 ] 1 / 2 Formula 10.

5. The method for determining the construction window period of an offshore trestle under the wind-wave-current coupling effect according to claim 4 is characterized in that: In the step of judging whether the vibration comfort of the operator (5) on the offshore construction trestle (1) in a certain continuous time period is less than or equal to the preset allowable comfort limit of the operator (5) on the offshore construction trestle (1), the preset allowable vibration comfort limit of the operator (5) on the offshore construction trestle (1) is A, wherein A is between 0.315 and 1.0, and the specific value is determined by the construction party based on the balance between construction safety and construction period. The smaller A is, the lower the construction safety of the operator but the shorter the construction period, and the larger A is, the higher the construction safety of the operator but the longer the construction period; if the vibration comfort of the operator (5) on the offshore construction trestle (1) in a certain continuous time period is less than or equal to A, that is, max(A w )≤A, then the continuous time period is regarded as the construction window period of the offshore construction trestle (1); if the vibration comfort level of the operator (5) on the offshore construction trestle (1) is greater than A in a certain continuous time period, that is, max(A w )>A, then this continuous time period cannot be used as the construction window period for the offshore construction trestle (1).

6. The method for determining the construction window period of an offshore trestle under the wind-wave-current coupling effect according to claim 5 is characterized in that: When the structure of the offshore construction trestle (1) is determined, the vibration comfort level A of the operator (5) on the offshore construction trestle (1) during a certain continuous period of time is p The water level h and the average wind speed U at a height of 10 meters over ten minutes at the bridge are 10 , significant wave height H in engineering sea area w , wave average period T w , wave propagation direction α w It is determined by environmental parameters such as the ocean current velocity v0 and can be expressed using Formula 11 as follows: A p =f(h,U 10 ,H w ,T w ,α w ,v0) Formula 11 The comfort level A of the operator (5) on the offshore construction trestle (1) under the coupling of wind, wave and current in a certain continuous time period p When formula 12 is satisfied, the continuous time period is used as the construction window period of the offshore construction trestle (1); A p = f(h, U 10 , H w , T w , α w , v0) < A Equation 12.

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