CN104778375A - Classifying-quantization submarine cable risk evaluation probability analysis method - Google Patents

Abstract

The invention belongs to the technical field of submarine cable engineering and particularly relates to a classifying-quantization submarine cable risk evaluation probability analysis method. By comprehensive analysis of the environment of a submarine cable, a risk source of the submarine cable is identified, a classifying-quantization risk evaluation probability model is established for a main risk source, by model computing, the accident recurrence interval of the submarine cable under different protecting situations can be obtained, and the problems such as probability calculation of human risks, especially anchor damage risks are solved. By classifying-quantization evaluation on submarine cable engineering risks, the protecting scheme of the submarine cable can be formulated in a targeted mode, the safety and the reliability of submarine cable operation are improved, and obvious economical and social benefit is achieved.

Description

A kind of subsea cable risk assessment probability analysis method of classification quantitative

Technical field

The invention belongs to subsea cable field of engineering technology, be specifically related to a kind of subsea cable risk assessment probability analysis method of classification quantitative.

Background technology

Along with technical progress and the economic development of China, particularly country's the implementing in full of " "Oceanic" strategy ", subsea cable power transmission engineering presents fast-developing feature in recent years.Subsea cable engineering normally connects the important channel that both sides, straits electrical network or continent power to island, and often involve great expense, repairing of constructing is extremely complicated, once break down, system is by off-the-line, and consequence is serious.Therefore, the safety of subsea cable, reliability service are most important.

In project engineering stage, accurately judge risk source that cable faces, the safe operation of cable after risk class that Efficient Evaluation cable faces concerns engineering input and engineering puts into operation.

Domestic and international subsea cable engineering at early construction often with reference to the engineering experience such as petroleum pipe line, the method taked omnidistance mechanical protection or do not protect.This way does not combine with practical risk situation, does not carry out quantum chemical method to risk situation, risk probability yet.Therefore, although domestic and international existing some built subsea cable engineerings, really few for the work that subsea cable risk assessment is carried out, almost there is no the experience that can directly use for reference.

Based on this, be necessary the marine environment faced for subsea cable, in conjunction with subsea cable self-characteristic, identification carried out to the risk source of subsea cable, propose a kind of subsea cable risk assessment probability analysis method of classification quantitative.

Summary of the invention

Object of the present invention is exactly the deficiency existed to solve above-mentioned background technology, provides a kind of subsea cable risk assessment probability analysis method of classification quantitative.This method is carried out on the basis of identification at the risk source faced subsea cable, based on the concept of risk, proposes the Probability Analysis and Calculation method for different risk source.

The technical solution used in the present invention is: a kind of subsea cable risk assessment probability analysis method of classification quantitative, comprises the following steps:

(1) according to geography and the geologic media at Submarine Cable Laying place, the risk source of subsea cable is determined;

(2) statistical study is carried out to the risk source of subsea cable, obtain the main hazard source affecting subsea cable safety, comprise that junk hits, shipwreck hits, stranded shock, drag anchor is hit and the anchor that falls hits;

(3) for main hazard source dissimilar in step 2, the risk evaluation model set up classification respectively, quantizing;

(4) solve the risk evaluation model in dissimilar main hazard source, the risk evaluation model in dissimilar main hazard source is added and namely obtains the accident reproduction phase.

Further, the depth of water of the geography at Submarine Cable Laying place and geologic media comprise fishing ground environment in described step (1), the frequent degree of harbour marine activity of cable debarkation point, water route ship cast anchor situation, sanidal length and route.

Further, in described step (1), the risk source of subsea cable comprises cable self risk, natural risk and human risks, wherein:

The risk that self risk of described cable is the type of subsea cable, material, structural factor cause;

The risk that described natural risk is subsea geological environment, geologic condition factor causes, comprises submarine slide, landslide, sediment movement and earthquake;

Described human risks is mainly the risk that sea human activity causes, comprise fishing, cast anchor, drilling well, sea ship operation.

Further, setting up the risk evaluation model that junk hits in described step (3) is:

$P_{\mathrm{hit},\mathrm{sl},r}=P_{\mathrm{hit},r}\·\frac{L_{\mathrm{sl}}\·(D+B/2+B/2)}{A_r}$

P in formula _{hit, sl, r}for within the scope of annual annular radius r, junk hits the probability on subsea cable; P _{hit, r}for hitting the probability in annular extent; L _slfor the length of subsea cable in annular extent; D is subsea cable diameter, and B is junk width, A _rfor radius is the annulus area of r;

Wherein

P _hit,r＝P(r _i＜x≤r ₀)＝P(x≤r ₀)-P(x≤r _i)

$P(x\≤r)=\underset{-r}{\overset{r}{\∫}}p\left(x\right)\mathrm{dx}$

$p\left(x\right)=\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\δ}}{e}^{\frac{1}{2}}{\left(\frac{x}{\mathrm{\δ}}\right)}^2$

In formula, p (x) arrives sub sea location for falling object and falls the probability density of the horizontal range x between drop point site, and x is the horizontal range that falling object offsets in seabed, and δ is lateral excursion distance, r _ifor the least radius in annular extent, r ₀for the maximum radius in annular extent.

Further, setting up the risk evaluation model that shipwreck hits in described step (3) is:

$F_{\mathrm{Hit}}=\frac{{2L}_{\sin k}S}{A_{\sin k}}\·P_a$

F in formula _hitfor shipwreck hits the probability of subsea cable; P _afor the ratio of Ship's Sinking, L _sinkfor the captain of the ship that sinks, S is the length of exposure of cable; A _sinkcrucial shipwreck region area.

Further, the risk evaluation model setting up stranded shock in described step (3) is:

F _Hit＝K ₁P _ShipP _ac

F in formula _hitfor annual stranded vessel hits the probability of subsea cable; P _acfor Calculation of Ship Grounding's Probability, K ₁for considering to drift about stranded modifying factor in cable area; P _shipfor enough large-sized boats and ships can cause the ratio of cable bad in region.

Further, setting up the risk evaluation model that drag anchor hits in described step (3) is:

$F_{\mathrm{Hit}}=N_{\mathrm{ship}}\left[{1-P}_{\mathrm{Human}}\right]F_{\mathrm{Drift}}\frac{\mathrm{\α}}{V_{\mathrm{ship}}\·1852}{P}_{\mathrm{Hit}}$

F in formula _hitfor the probability of subsea cable is caught in annual drag anchor; N _shipfor being had the quantity of the possible boats and ships of anchoring by extra large cable route section; F _driftfor drift frequency; P _humanfor the probability do not cast anchor; V _shipfor speed of the ship in metres per second; α is by the length of dragging before being anchored on seabed; P _hitfor the anchor that falls hits the probability of extra large cable at every turn.

Further, setting up the risk evaluation model that anchor hits in described step (3) is:

F _Hit＝N _ShipF _Drift[1-P _Humman]P _LossP _Hit

F in formula _hitfor the anchor that falls every year hits the probability of subsea cable; N _shipfor being had the quantity of the possible boats and ships of anchoring by extra large cable route section; F _driftfor drift frequency; P _humanfor not carrying out the probability cast anchor near extra large cable; P _losswhen operating when casting anchor, crewman is to the out of control probability of anchor; P _hitfor the anchor that falls hits the probability of extra large cable at every turn.

The present invention, by the comprehensive analysis in bad border residing for subsea cable, picks out the risk source of subsea cable.The risk assessment probability model set up classification for main hazard source, quantizing, can be calculated the accident reproduction phase of subsea cable in different protection situation by model.The present invention is that first Application is in the risk assessment probability analysis method of subsea cable in the world, and emphasis solves the problems such as human risks, the especially calculating of anchor evil risk probability.By assessing the classification quantitative of subsea cable engineering risk, the protection scheme of subsea cable can be formulated with a definite target in view, improving the safe reliability that subsea cable runs, there is significant economic and social benefit.

Accompanying drawing explanation

Fig. 1 is process flow diagram of the present invention.

Fig. 2 is the track schematic diagram of junk in water.

Fig. 3 is the offset distance schematic diagram of junk in water.

Fig. 4 is the schematic diagram that subsea cable is hit by junk.

Fig. 5 is the Atlantic telecommunication cable damage reason schematic diagram.

Fig. 6 is accident probability contrast schematic diagram under the different protection scheme of Hainan interconnection project.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail, is convenient to be well understood to the present invention, but they do not form restriction to the present invention.

Subsea cable in connection with the main electrical network in both sides of the Straits usually, is laid in seabed, and the while that systematic affinity being important, repair and maintenance difficulty, can affect the safe and stable operation of the main electrical network in two ends once break down.For Hainan interconnection project; Hainan interconnection project is China's first UHV (ultra-high voltage), long distance, jumbo networking project over strait; in connection with south electric network major network and Hainan Power Grid; status is important, and simultaneously because subsea cable is across Qiongzhou Strait, sea frequent activity, marine environment are complicated; classification quantitative assessment is carried out to the risk of Submarine Cable of Hainan Interconnection Project; determine the risk class of subsea cable, formulate protection scheme targetedly, most important to the safe and stable operation of subsea cable.

A subsea cable risk assessment probability analysis method for classification quantitative, comprises the following steps:

1, according to geography and the geologic media at Submarine Cable Laying place, the risk source of subsea cable is determined:

Concerning different waters, different type of cable, damage reason comparatively disperses, and principal risk type also has larger difference.Figure 5 shows that the reason of the telecommunication cable damage in the Atlantic.The risk that cable in shallow sea is subject to fishing gear damage than the cable of waterfront area is larger, and sea electric power cable protect owing to there being armouring, higher than very thin submarine communication cable intensity a lot, the fish be subject to bite affect less.The mainly impact that causes of some local fried fish tartar souce of other reasons in Fig. 5, the operating experience of subsea cable shows, most of extra large cables the disrumpent feelings artificial origin of being cause.

Extra large cable oneself factor, natural risk and human risks is mainly comprised in conjunction with the cable application of sea, countries in the world, operation and accident conditions known subsea cable dangerous matter sources.(1) extra large cable oneself factor.Subsea cable oneself factor comprises: 1) extra large cable type; 2) extra large cable material; 3) extra large cable structure.(2) natural risk.The natural risk that subsea cable faces comprises: 1) submarine slide; 2) seabed landslide; 3) sediment movement; 4) seismic activity; 5) wash away; 6) biodyne.(3) human risks.Human risks comprises: 1) fishing operation; 2) cast anchor; 3) dredging and (or) drilling well; 4) cable ship operation.Human risks can be categorized as that junk hits, shipwreck hits, stranded shock, drag anchor are hit, the anchor that falls hits medium form.

Such as the disaster such as earthquake, landslide can destroy cable, but the main destructive factor of subsea cable or mankind's activity, and the fault of most of submarine communication cable and sea electric power cable is all caused by the injury of fishing gear and anchor.

2, statistical study is carried out to the risk source of subsea cable, obtains the main hazard source affecting subsea cable safety:

Self risk of 2.1 subsea cables

Hainan interconnection project subsea cable used is the oil-filled subsea cable of self-dissolving formula, and submarine cable armoring layer is made up of the cold-drawn flat type copper wire of a formable layer, and be used for protection cable from external mechanical damage, subsea cable self risk factors are less.

2.2 subsea cable natural risks

Subsea cable path selection phase has avoided frequent activity region, seabed, and the possibility that natural risk occurs is less, so its chief destructive factor is the activity of the mankind.

2.3 subsea cable human risks

(1) junk risk

The junk fallen down from passing ships or neighbouring operation ship can cause the breakage of subsea cable.Such as, to the maintenance of subsea cable, build new submarine cable, build the relevant ship in new harbour all can have junk may, and the kind of junk mainly building pipe, various container and construction/service equipment.Because Hainan interconnection project Hai Lanbaohuqu selects not close on harbour, simultaneously take pre-ditching protected mode logging in end, the impact therefore by port construction is less.The case event that falls of container ship happens occasionally in shipping process, but is under extreme weather conditions.Qiongzhou Strait periphery snug anchorage enriches, and the possibility that the container ship of large-tonnage rank generally navigates by water in extreme circumstances is little, so the probability that this event occurs is very low.

(2) shipwreck risk

The accident that shipwreck causes cable and optical cable to lose efficacy mostly is shipwreck discarded object and moves under flow action and have influence on cable and optical cable.Submarine Cable of Hainan Interconnection Project planning route does not exist the moving objects such as shipwreck, and the risk of directly pounding after shipwreck on cable is also very low.

(3) ship risk out of control

Certain meteorological with under hydrologic condition, because strong wind and the spontaneous phenomenon such as to surge cause ship drift out of control, the event of then casting anchor still exists, and this kind of rear ship cast anchor out of control can have influence on the security of subsea cable.The principal element of boats and ships drift out of control is caused to be: meteorological and water level condition causes ship to drift about; Ship self is out of control.It is malfunctioning suddenly that ship main cause out of control is that these boats and ships produce car, rudder for various reasons, so that boats and ships are out of control, has to take emergency brake measure.

The motion process of boats and ships drift out of control can be divided into two stages, and one is the inertial deceleration stage, available inertial stopping distance theoretical analysis ship motion process, calculating relevant data; Two is with the trickling boat stage, can carry out analytical calculation according to the streamflow regime of setting.Due to cable singularity through marine site, with the trickling boat stage due to flow velocity with flow to uncertain, cannot determine to drop down boat direction and position by accurate quantivative approach, and stage that to be ship collision energy maximum in inertial deceleration stage.Therefore the main boats and ships drift value considering the inertial deceleration stage, by the estimation of these drift values, the possibility of casting anchor that boats and ships are potential can be recognized.

1) stroke, calculate when rushing

When rushing, (T) refers to from out of control to inertia disappearance required time.Its large I is asked for by formula A-1:

${V=V}_0\·e^{-t/T_{\mathrm{st}}}---(A-1)$

In formula (A-1) V be boats and ships in stroke interval, the ship's speed (m/s) of any time; V ₀for boats and ships initial time ship's speed (m/s); T _stfor boats and ships constant deceleration time, T _st=C/ln2, C can table look-up according to water discharge and obtain, as shown in Table A-1.

Table A-1C is worth table

2) hydrostatic stroke (S ') refers to when rushing in T time, and boats and ships are along the distance of ship's speed direction movement, and available formula A-2 calculates.

${{\∫}_0}^T{V}_0\·e^{-\frac{T}{\mathrm{Tu}}}\mathrm{dt}=V_0{T}_{\mathrm{st}}(1-e^{-T/T_{\mathrm{st}}})---(A-2)$

For 5 tons and following boats and ships, its stroke is less than 2nmile, for 10 tons and its stroke of above boats and ships more than 2nmile.Under normal circumstances, the usual practice of flight-line design is that course line and extra large cable prohibited area or protected location at least keep transfer 2nmile.By this usual way, 5 tons and following boats and ships are through inertial drift after out of control, and when boats and ships drift to extra large cable protection district Its Adjacent Waters, its inertia has disappeared or substantially disappeared, and the risk that drag anchor affects cable is less than 10 tons.

(4) fishing activity risk

Sea electric power cable is higher than the intensity of submarine communication cable, and can resist the damage of some fishing gears and threaten, networking project cable protection district is set to the district that bans catching, and add that the high stream of this district's wave is anxious, two sides fisherman is main at open-ocean fishing fixation, and inshore fishing operation is less.Fishing operation is very little to the threat of Qiongzhou Strait subsea cable, and need the mainly fishing boat anchor evil of the risk from fishing operation considered, anchor evil mainly comprises casts anchor and drag anchor.

1) cast anchor

The possibility of casting anchor depends primarily on the position of maritime affairs situation, port and pier busy extent and anchorage near extra large cable protection district.In navigation channel, all ships should remain navigation, and any casting anchor all probably causes falling afterwards the shock of anchor, so the possibility of accident of casting anchor in the middle of navigation channel is little.And Qiongzhou Strait cable also has many anchorage regardless districts specified along the line, especially PORT OF MACUN, but or potential risk of casting anchor.

A) anchorage regardless district is generally used for berthing preferential ship entered harbor or waiting for that the ship of pilot boat berths.Just there is the possibility that anchorage regardless district mistake is cast anchor in this.Meanwhile, after anchorage regardless district is fully parked with, often have boats and ships region riding at anchor nearby.

B) primary channel of the North Sea and the mouth of the Zhujiang River is not only in Qiongzhou Strait, and be that the North Sea and the mouth of the Zhujiang River water channel boats and ships are at typhoon and the main lee in monsoon season, before extreme climate occurs, wait for that the boats and ships that enter a port are before anchorage and enter in the process of anchorage, probably cast anchor, for the subsea cable across west section, Qiongzhou Strait, the harm of casting anchor is that ship anchor is thrown unintentionally across subsea cable temporarily, when some are urgent, also there will be interim casting anchor.

C) for the casting anchor of Hou Gang, drag anchor behavior temporarily, Qiongzhou Strait traffic hub VTS supervision department often can not predict in advance, and before being in extreme climate in whole emergency traffic management process, is very easy to occur that point is omitted in ship-handling.

2) drag anchor

Drag anchor is exactly after anchorage regardless, and anchor also will drag the situation of a segment distance at the bottom.Concrete length depends on speed during size, the ship drag anchor of ship and anchor.

That investigates according to Qiongzhou Strait submarine geology found that Hai Lanbaohuqu there is the vestige of all kinds of obvious drag anchor, and the vestige of drag anchor not only appears at region, transmeridional navigation channel, also go out the longitudinal region in north-south, and different water depth condition all has anchor trace.This illustrates that the reality of extra large cable protection area drag anchor is severeer.

2.4 networking subsea cable principal risk source, Hainan

In conjunction with the specific environment of Qiongzhou Strait and subsea cable Route Area, the main hazard source of Submarine Cable of Hainan Interconnection Project is anchor evil, comprises falling anchor and drag anchor two kinds of forms.

3, for dissimilar main hazard source, the risk evaluation model set up classification, quantizing:

3.1 junks hit risk evaluation model

Sea junk may hit cable, because cable itself has armouring protection, adds later stage covering protection, and small-sized and lightweight object falls and do not produce threat to subsea cable.Junk path in water is mainly relevant with body form, weight.Experimental observation show junk in water main trajectory pattern as shown in Figure 1, a, d, e are mainly tube track, rectangle, circular object track are as shown in b, c, f.The track of object in seabed is distributing just very much of deviation angle, shown in (1),

$p\left(x\right)=\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\δ}}{e}^{\frac{1}{2}}{\left(\frac{x}{\mathrm{\δ}}\right)}^2---\left(1\right)$

In formula (1), p (x) arrives sub sea location for falling object and falls the probability density of the horizontal range x between drop point site, x is the horizontal range that falling object offsets in seabed, δ is lateral excursion distance, and d is the degree of depth of falling object in seabed, and offset distance as shown in Figure 2.

All kinds of object displacement angle is as shown in table 1.

Table 1 different objects deviation angle

Object hits cable schematic diagram as shown in Figure 3, cable by the probability that hits such as formula shown in (2)

$P_{\mathrm{hit},\mathrm{sl},r}=P_{\mathrm{hit},r}\·\frac{L_{\mathrm{sl}}\·(D+B/2+B/2)}{A_r}---\left(2\right)$

P in formula (2) _{hit, sl, r}for hitting the probability on subsea pipeline within the scope of annual annular radius r; P _{hit, r}for hitting the probability in annular extent; L _slfor the length of subsea pipeline in annular extent; D is subsea cable diameter, and B is junk width, the annulus area of A to be radius be r.

P _{hit, r}shown in (3).

P _hit,r＝P(r _i＜x≤r ₀)＝P(x≤r ₀)-P(x≤r _i)

$P(x\≤r)=\underset{-r}{\overset{r}{\∫}}p\left(x\right)\mathrm{dx}---\left(3\right)$

R in formula (3) _ifor the least radius in annular extent, r ₀for the maximum radius in annular extent.

3.2 shipwrecks hit risk evaluation model

Shipwreck can be considered a kind of special junk.Its risk evaluation model is consistent with junk risk probability computing method.Annual shipwreck hits the probability of subsea cable such as formula shown in (4).

$F_{\mathrm{Hit}}=\frac{{2L}_{\sin k}S}{A_{\sin k}}\·P_a---\left(4\right)$

P in formula _afor the ratio of Ship's Sinking, L _sinkfor the captain of the ship that sinks, S is the length of exposure of cable; A _sinkcrucial shipwreck region area.

3.3 stranded shock risk evaluation models

Cable logs in district, and boats and ships drift is stranded may hit subsea cable, and Calculation of Ship Grounding's frequency and every bar ship cause the probability that sinks relevant due to collision.Stranded vessel hits the probability of subsea cable such as formula shown in (5),

F _Hit＝K ₁P _ShipP _ac(5)

F in formula (5) _hitfor annual stranded vessel hits the probability of subsea cable; P _acfor Calculation of Ship Grounding's Probability, K ₁for considering to drift about stranded modifying factor in cable area; P _shipfor enough large-sized boats and ships can cause the ratio of cable bad in region.

3.4 drag anchor risk evaluation models

The situation of boats and ships drag anchor damage subsea cable is more common in the accident of cable by outer damage, is important risk factors.Cast anchor is consider when boats and ships run out of steam, such as, apart from the emergency brake in a certain ultimate range of marine anchorage.The possibility that this ultimate range is drifted about to subsea cable direction under being included in the impact of disadvantageous wind and ocean current.After anchor is thrown seabed, thrust sea bed mainly through anchor and utilize the resistance of soil to provide counter-force thus fixing ship.The counter-force that soil can provide in the horizontal direction is much larger than the counter-force provided in the vertical direction, when the required anchor holding capacity provided is certain, the action direction of anchor chain and the horizontal sextant angle in mud face less, its anchor holding capacity that can provide is larger, otherwise the larger anchor holding capacity of angle is less.

Drag anchor catches on the probability of subsea cable such as formula shown in (6):

$F_{\mathrm{Hit}}=N_{\mathrm{ship}}\left[{1-P}_{\mathrm{Human}}\right]F_{\mathrm{Drift}}\frac{\mathrm{\α}}{V_{\mathrm{ship}}\·1852}{P}_{\mathrm{Hit}}---\left(6\right)$

F in formula (6) _hitfor the probability of subsea cable is caught in annual drag anchor; N _shipfor being had the quantity of the possible boats and ships of anchoring by extra large cable route section; F _driftfor drift frequency; P _humanfor the probability do not cast anchor; V _shipfor speed of the ship in metres per second; α is by the length of dragging before being anchored on seabed; P _hitfor the anchor that falls hits the probability of extra large cable at every turn, conservative estimation value is 1.0, and supposes that ship and cable pass perpendicularly through.

3.5 fall anchor risk evaluation model

Except anchor catches on the risk of cable, the risk that the anchor that falls hits cable also should be considered.Similar with drag anchor, the situation of boats and ships emergency brake when running out of steam only considered by the anchor that falls.The anchor that falls hits the probability of cable such as formula shown in (7):

F _Hit＝N _ShipF _Drift[1-P _Humman]P _LossP _Hit(7)

F in formula (7) _hitfor the anchor that falls every year hits the probability of subsea cable; N _shipfor being had the quantity of the possible boats and ships of anchoring by extra large cable route section; F _driftfor drift frequency; P _humanfor not carrying out the probability cast anchor near extra large cable; P _losswhen operating when casting anchor, crewman is to the out of control probability of anchor; P _hitfor the anchor that falls hits the probability of extra large cable at every turn.

The main hazard source of Submarine Cable of Hainan Interconnection Project is anchor evil, and fall anchor and drag anchor risk probability are such as formula shown in (6), formula (7).For carrying out accurate classification quantitative assessment, according to submarine geology condition, subsea cable Route Area can be divided into A district, B district, C district, D district, E district, Table A-2 between concrete zoned format.

Table A-2 subsea cable Route Area divides

Risk class is relevant with protection of submarine cable form, according to the geographic position of Submarine Cable of Hainan Interconnection Project, navigation channel, anchorage, geologic condition, the factor such as protocol requirement and executive cost, devises following five kinds of extra large cable protection schemes.

Scheme 1: the section of logging in carries out pre-ditching in both sides: the north section of logging in (KP0-KP3.3) marine site is more shallow, easy construction, suggestion is pre-ditching directly; The south section of logging in (KP29.8-KP30.5) sea bed sandy clay has and much rolls rock, depth of water 0-10 rice, suggestion cleaning is pre-ditching after rolling rock.Interlude does not take any safeguard measure, and cable is directly exposed is positioned over seabed.

Scheme 2: carry out pre-ditching protection according to scheme 1 pair of both sides section of logging in.Carry out punching in some areas of interlude (KP3.3-KP29.8) and bury protection, hit determine buried depth according to BPI 1.5, anti-1 ton of anchor, do not carry out jackstone protection.

Scheme 3: carry out pre-ditching protection according to scheme 2 pairs of both sides sections of logging in and interlude and protection is buried in punching.Carry out jackstone protection in some areas of main channel (KP5-KP19), hit according to anti-1 ton of anchor and determine rock weir size.

Scheme 4: carry out pre-ditching protection according to scheme 2 pairs of both sides sections of logging in and interlude and protection is buried in punching.Carry out jackstone protection at remaining all regions, hit according to anti-1 ton of anchor and determine rock weir size.

Scheme 5: carry out pre-ditching protection according to scheme 1 pair of both sides section of logging in.Carry out punching in some areas of interlude (KP3.3-KP29.8) and bury protection, hit determine buried depth according to BPI 1.5, anti-2 tons of anchors, carry out jackstone protection at remaining all regions, hit according to anti-2 tons of anchors and determine rock weir size.

4, solve the risk evaluation model in dissimilar main hazard source, be added by the risk evaluation model in dissimilar main hazard source, draw the accident reproduction phase, formulating for cable venture analysis and protection scheme provides reference.

According to protection schemes different in step 3; and in conjunction with the ship type of each section and quantity situation, classification quantitative calculating being carried out to the risk situation under each protection scheme of subsea cable, the anchor that fallen by subsea cable damages and drag anchor damage considers for subsea cable accident probability.Subsea cable accident rate statistics is as shown in Table A-3, and Fig. 6 is shown in each protection scheme subsea cable accident rate contrast.

Accident rate under the different protection scheme of Table A-3 two times extra large cables and reoccurrence period

Different section subsea cable classification quantitative risk evaluation result under can drawing different protection scheme by Fig. 6 and Table A-3.The accident reproduction phase can be calculated according to accident probability.Can see cable protection scheme 1 of going to sea, the accident reproduction phase of scheme 2 is respectively 36.36,47.69, southern major network and 50 years designed lives of Hainan Power Grid networking project subsea cable, from result of calculation, scheme 1, scheme 2 do not meet the demands.The accident reproduction phase of scheme 3, scheme 4, scheme 5 is respectively 51.45,51.46 and 77.19; requirement designed life can be met; but scheme 4 only improves 0.01 than the scheme 3 accident reproduction phase; protection cost but significantly improves; the safe class of scheme 5 is the highest; but protection cost is too high, less economical.Therefore, southern major network and Hainan Power Grid networking project subsea cable is recommended to adopt protection scheme 3.

The content be not described in detail in this instructions belongs to the known prior art of professional and technical personnel in the field.

Claims (8)

1. a subsea cable risk assessment probability analysis method for classification quantitative, is characterized in that, comprise the following steps:

(1) according to geography and the geologic media at Submarine Cable Laying place, the risk source of subsea cable is determined;

(2) statistical study is carried out to the risk source of subsea cable, obtain the main hazard source affecting subsea cable safety, comprise that junk hits, shipwreck hits, stranded shock, drag anchor is hit and the anchor that falls hits;

(3) for main hazard source dissimilar in step 2, the risk evaluation model set up classification respectively, quantizing;

(4) solve the risk evaluation model in dissimilar main hazard source, the risk evaluation model in dissimilar main hazard source is added and namely obtains the accident reproduction phase.

2. the subsea cable risk assessment probability analysis method of a kind of classification quantitative according to claim 1, is characterized in that: the depth of water of the geography at Submarine Cable Laying place and geologic media comprise fishing ground environment in described step (1), the frequent degree of harbour marine activity of cable debarkation point, water route ship cast anchor situation, sanidal length and route.

3. the subsea cable risk assessment probability analysis method of a kind of classification quantitative according to claim 1, is characterized in that: in described step (1), the risk source of subsea cable comprises cable self risk, natural risk and human risks, wherein,

The risk that self risk of described cable is the type of subsea cable, material, structural factor cause;

The risk that described natural risk is subsea geological environment, geologic condition factor causes, comprises submarine slide, landslide, sediment movement and earthquake;

Described human risks is mainly the risk that sea human activity causes, comprise fishing, cast anchor, drilling well, sea ship operation.

4. the subsea cable risk assessment probability analysis method of a kind of classification quantitative according to claim 1, is characterized in that, sets up the risk evaluation model that junk hits to be in described step (3):

$P_{\mathrm{hit},\mathrm{sl},r}=P_{\mathrm{hit},r}\·\frac{L_{\mathrm{sl}}\·(D+B/2+B/2)}{A_r}$

P in formula _{hit, sl, r}for within the scope of annual annular radius r, junk hits the probability on subsea cable; P _{hit, r}for hitting the probability in annular extent; L _slfor the length of subsea cable in annular extent; D is subsea cable diameter, and B is junk width, A _rfor radius is the annulus area of r;

Wherein

P _hit,r＝P(r _i＜x≤r ₀)＝P(x≤r ₀)-P(x≤r _i)

$P(x\≤r)=\underset{-r}{\overset{r}{\∫}}p\left(x\right)\mathrm{dx}$

$p\left(x\right)=\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\δ}}{e}^{\frac{1}{2}{\left(\frac{x}{\mathrm{\δ}}\right)}^2}$

In formula, p (x) arrives sub sea location for falling object and falls the probability density of the horizontal range x between drop point site, and x is the horizontal range that falling object offsets in seabed, and δ is lateral excursion distance, r _ifor the least radius in annular extent, r ₀for the maximum radius in annular extent.

5. the subsea cable risk assessment probability analysis method of a kind of classification quantitative according to claim 1, is characterized in that, sets up the risk evaluation model that shipwreck hits to be in described step (3):

$F_{\mathrm{Hit}}=\frac{{2L}_{\sin k}S}{A_{\sin k}}\·P_a$

F in formula _hitfor annual shipwreck hits the probability of subsea cable; P _afor the ratio of Ship's Sinking, L _sinkfor the captain of the ship that sinks, S is the length of exposure of cable; A _sinkcrucial shipwreck region area.

6. the subsea cable risk assessment probability analysis method of a kind of classification quantitative according to claim 1, is characterized in that, the risk evaluation model setting up stranded shock in described step (3) is:

F _Hit＝K ₁P _ShipP _ac

F in formula _hitfor annual stranded vessel hits the probability of subsea cable; P _acfor Calculation of Ship Grounding's Probability, K ₁for considering to drift about stranded modifying factor in cable area; P _shipfor enough large-sized boats and ships can cause the ratio of cable bad in region.

7. the subsea cable risk assessment probability analysis method of a kind of classification quantitative according to claim 1, is characterized in that, sets up the risk evaluation model that drag anchor hits to be in described step (3):

$F_{\mathrm{Hit}}=N_{\mathrm{ship}}[1-P_{\mathrm{Human}}]F_{\mathrm{Drift}}\frac{\mathrm{\α}}{V_{\mathrm{ship}}\·1852}{P}_{\mathrm{Hit}}$

F in formula _hitfor the probability of subsea cable is caught in annual drag anchor; N _shipfor being had the quantity of the possible boats and ships of anchoring by extra large cable route section; F _driftfor drift frequency; P _humanfor the probability do not cast anchor; V _shipfor speed of the ship in metres per second; α is by the length of dragging before being anchored on seabed; P _hitfor the anchor that falls hits the probability of extra large cable at every turn.

8. the subsea cable risk assessment probability analysis method of a kind of classification quantitative according to claim 1, is characterized in that, sets up the risk evaluation model that anchor hits in described step (3) to be:

F _Hit＝N _ShipF _Drift[1-P _Humman]P _LossP _Hit

F in formula _hitfor the anchor that falls every year hits the probability of subsea cable; N _shipfor being had the quantity of the possible boats and ships of anchoring by extra large cable route section; F _driftfor drift frequency; P _humanfor not carrying out the probability cast anchor near extra large cable; P _losswhen operating when casting anchor, crewman is to the out of control probability of anchor; P _hitfor the anchor that falls hits the probability of extra large cable at every turn.