JP6570861B2 - Behavior estimation method for cross-fault buried pipeline and behavior estimation device for cross-fault buried pipeline - Google Patents

Description

  The present invention relates to a behavior estimation method for a cross-fault buried pipe and a cross-fault buried pipe behavior estimation apparatus in which a plurality of pipes are joined via a seismic joint having a reference allowable bending angle α and a maximum allowable bending angle β.

  As shown in FIGS. 1 (a) and 1 (b), when ground subsidence or cracking occurs in the ground where a pipe line in which a plurality of pipes 1 are joined via an earthquake-resistant joint, such as an earthquake-resistant joint ductile iron pipe, is embedded. Even if the amount of expansion or contraction or the bending angle of one joint reaches the limit, a large ground displacement is absorbed by the behavior of the adjacent joint.

  FIG. 1 (c) shows the expansion / contraction behavior of the joint portion of an NS-type ductile iron pipe, which is an example of such an earthquake-resistant joint ductile iron pipe. The upper row shows the standard state, the middle row shows the contracted state, and the lower row shows the extended state. In the figure, reference numeral 2 denotes a receiving port, reference numeral 3 denotes an insertion opening, reference numeral 4 denotes a rubber ring, and reference numeral 5 denotes a lock ring. The expansion / contraction amount of the seismic joint is ± 1% of the pipe length, the pulling strength is 3D (kN), D is the nominal diameter mm, the standard allowable bending angle α is about 4.9 °, and the maximum allowable bending angle β is about 8 °. It is.

  In Patent Document 1, as a maintenance management method that can evaluate the soundness of uneven settlement of piping systems including mechanical joints, the subsidence distribution of the ground is measured along the underground pipe line with mechanical joints. Then, the local relative subsidence amount δr and the length L of the generation range are obtained from the subsidence distribution, and the maximum bending angle θmax of the mechanical joint included in the generation range is set to θmax ≦ 2 arctan (2δr / L). A maintenance method for evaluating the soundness of the piping system by comparing the angle θmax with the allowable bending angle of the mechanical joint has been proposed.

JP 7-248100 A

  According to the maintenance management method for evaluating the soundness of the piping system described above, the bending angle of the mechanical joint is calculated based on the ground subsidence distribution measured on the ground surface, and the calculated bending angle is compared with the allowable bending angle. Therefore, the soundness of the existing piping system can be evaluated.

  However, in Japan, which is said to have entered the period of earthquake activity, it is recognized that there is a need to evaluate the soundness by estimating the behavior of buried pipes across faults. Besides, there is still no practical behavior estimation method for that purpose. In addition to the existing pipelines, the behavior of the cross-fault buried pipes is estimated in order to estimate the behavior of the cross-fault buried pipes and to design with sufficient safety in mind. There is a need for a method.

  In view of the above problems, an object of the present invention is to provide a cross-fault buried pipe behavior estimation method and a cross-fault buried pipe behavior estimation apparatus that can easily obtain accuracy without using a large-scale simulation apparatus. is there.

In order to achieve the above-mentioned object, the first characteristic configuration of the method for estimating the behavior of a cross-fault buried pipe according to the present invention is as described in claim 1 of the claims, and the standard allowable bending angle α, maximum through the seismic joint allowable bending angle β a behavior estimation method of a tomographic cross buried duct in which a plurality of tubes are joined, the movement of the ground flexion is due to fault displacement of a portion of the seismic joint before Symbol line exceeds the reference allowable bending angle α is the limit to bend to follow the, executed if you displaced relative movement of the ground, fault after reaching the fault displacement amount reaching the reference allowable flexion angle α The displacement influence degree k indicating the ratio of the displacement amount δj of the partial seismic joint to the fault displacement excess amount δ, which is the displacement amount, is determined for each of the at least two objective variables P1 and P2 determined based on the quantification theory class 1. Estimation using category coefficients P1i and P2i Formula _{k = P 1i · x 1i +} P 2i · x 2i (x 1i, x 2i is 0 or 1)
A displacement influence estimating step of obtaining at said calculated bending angles θ a behavior of seismic joint for assumed fault displacement amount based on the displacement influence k estimated by the displacement influence estimating step, the bending angle θ which issued calculated It is possible to evaluate the safety of the earthquake resistant joint with respect to the assumed fault displacement amount based on the above , or the behavior of the earthquake resistant joint is less than the maximum allowable bending angle β based on the displacement influence degree k estimated in the displacement influence degree estimating step. A seismic resistance that calculates a fault displacement amount at a predetermined bending angle θ, and can evaluate the safety of the earthquake-resistant joint with respect to the bending angle θ based on whether the calculated fault displacement amount is smaller than the predicted fault displacement amount. seen including a joint behavior estimating step, wherein the P1 is a nominal diameter of the tube, the P2 is the length of the tube, the inclination of the fault lies in a one or a combination of the position of the seismic joint.

When the bending angle of the earthquake-resistant joint exceeds the reference allowable bending angle α, the ground and the pipe line that fluctuate due to the fault are displaced, and the degree of the displacement is estimated by the displacement influence degree k. The displacement influence degree k is calculated by the displacement influence degree estimation step based on the coefficient for each category of the objective variable obtained in advance based on the quantification theory type 1, and the bending angle θ or the fault displacement is calculated based on the displacement influence degree k. A quantity is calculated. Accordingly, each time there is no need to parse an expensive simulation apparatus, ing as very easily bend angle θ or fault displacement amount is calculated.

Purpose variable nominal diameter is a design item for safety assessment of the conduit as, the displacement influence k by the length or the like of the tube is calculated to change the design value based on the results of behavior estimation conduit Even if necessary, it will be easier to define the change guidelines.

The second feature structure, as described in the claim 2, in addition to the first characteristic feature of the above, the portion of the seismic joint particular located in the vicinity of the boundary between the fault influence range and the non-affected area The point is that it is an earthquake-resistant joint.

  Since the specific seismic joint located near the boundary between the fault-affected area and the non-affected area is greatly bent, safety evaluation can be performed effectively.

As described in claim 3 , the third characteristic configuration includes the bending angle θ of the specific earthquake-resistant joint calculated in the earthquake-resistant joint behavior estimation step in addition to the second characteristic configuration described above. It exists in the point calculated | required by the difference of the pipe angle between the seismic joint adjacent to the side and a specific seismic joint, and the pipe angle between the seismic joint adjacent to a non-influence range side and a specific seismic joint.

In the fourth feature configuration, as described in claim 4 , in addition to any of the first to third feature configurations described above, the displacement influence degree k is a simulation result for a predetermined earthquake-resistant joint model. It is a value obtained by regression analysis so that the joint bending characteristic with respect to the fault displacement amount and the joint bending characteristic with respect to the fault displacement amount calculated based on the displacement displacement degree k of the joint with respect to the fault displacement amount substantially coincide. is there.

In the fifth feature configuration, as described in claim 5 , in addition to any of the first to fourth feature configurations described above, the bending angle θ of the earthquake-resistant joint with respect to the calculated assumed fault displacement amount is the maximum. The target variable category is determined so as not to exceed the allowable bending angle β, or the target variable category is set so that the fault displacement amount when the calculated bending angle θ becomes the maximum allowable bending angle β becomes the assumed fault displacement amount. It is in the point to ask for.

The sixth characterizing feature of the can, as noted in the claim 6, in addition the first above Fifth any feature configuration of lies in the tube is seismic joint ductile iron pipe.

The first characteristic configuration of the behavior estimation device for a cross-fault buried pipe according to the present invention is that, as described in claim 7 , a plurality of pipes are connected via an earthquake-resistant joint having a reference allowable bending angle α and a maximum allowable bending angle β. A device for estimating the behavior of a cross-fault buried pipe to be joined, which stores coefficients P1i and P2i of each category for at least two objective variables P1 and P2 determined based on the quantification theory class 1, and An input unit for selecting and inputting the category of the objective variable stored in the storage unit, and the bending angle of the some seismic joints exceeds a reference allowable bending angle α which is a limit of bending following movement of the ground due to fault displacement. Te, executed if you displaced relative movement of the ground, reads the coefficients of the desired category variable input by the input unit from the storage unit, the fault displacement amount reaching the reference allowable flexion angle α After reaching Displacement influence k an estimation equation _k = _{P 1i ·} x 1i indicating a ratio of a shift amount δj of the portion of the seismic joint for fault displacement overrun δ is a layer displacement _{+ P 2i · x 2i (x} 1i, x 2i Is 0 or 1)
A displacement influence estimating arithmetic unit for obtaining at the calculated bending angles seismic joint θ for assumed fault displacement amount based on the displacement influence k calculated by the displacement influence estimating arithmetic unit, the bending angle θ which issued calculated Based on the displacement influence degree k estimated in the displacement influence degree estimation step, it is possible to evaluate the safety of the earthquake resistant joint with respect to the assumed fault displacement amount , or the behavior of the earthquake resistant joint is a predetermined allowable bending angle β or less. A seismic joint that can calculate a fault displacement amount corresponding to a bending angle θ and evaluate safety of the seismic joint with respect to the bending angle θ based on whether the calculated fault displacement amount is smaller than a predicted fault displacement amount a behavior estimating arithmetic unit, seen containing a display unit, the displaying the calculation result by the seismic joint behavior estimation calculation unit, wherein P1 is the nominal diameter of the tube, the P2 is the length of the tube, the inclination of the fault, earthquake Any of the joint positions Or it is a point that is a combination .

  As described above, according to the present invention, it is possible to provide a cross-fault buried pipe behavior estimation method and a cross-fault buried pipe behavior estimation apparatus that can easily obtain accuracy without using a large-scale simulation apparatus.

(A) is a behavior explanatory diagram at the time of ground subsidence of a pipe joined by a seismic joint, (b) is a behavior explanatory diagram at the time of the ground crack, (c) is an explanatory diagram of expansion and contraction operation of the seismic joint. (A) is an active fault displacement distribution map, (b) is a model explanatory diagram showing the range of influence on the ground surface due to the slope of the fault (A) is explanatory drawing of joint spring and ground spring, (b)-(f) is a characteristic view of joint spring and ground spring. (A) is an explanatory diagram of an analysis model, (b) is an explanatory diagram of joint behavior due to a fault. (A) is an analysis result explanatory diagram of the joint bending angle of the fixed side boundary portion, (b) is an analysis result explanatory diagram of the joint bending angle of the displacement side boundary portion, and (c) is an analysis result explanatory diagram for a plurality of analysis conditions. (A) is an explanatory diagram of the analysis result of the behavior of the pipe line before and after the joint bending angle is the reference allowable bending angle α, and (b) and (c) are explanatory diagrams of the geometric model. Coordinate calculation explanatory diagram when calculating bending angle based on geometric model (A) is a comparison characteristic diagram of the analysis result and estimation result of the joint bending angle, (b) is a comparison characteristic diagram of the calculation result from the analysis result and estimation formula of the joint bending angle. (A) is an explanatory diagram of the objective variable for obtaining the displacement influence degree k, and (b) is an explanatory diagram of the objective variable and the coefficient of the category. Functional block diagram of the behavior estimation device for cross-fault buried pipes Flowchart explaining operation of behavior estimation device

  Hereinafter, a method for estimating the behavior of a cross-fault buried pipe and a behavior estimation device for a cross-fault buried pipe according to the present invention will be described taking an NS type ductile iron pipe as an example of a seismic joint ductile iron pipe as an example. Note that the present invention is not limited to NS type ductile iron pipes, and can be applied to all cross-fault buried pipes in which a plurality of pipes are joined via an earthquake-resistant joint having a reference allowable bending angle α and a maximum allowable bending angle β.

  The present invention geometrically models pipe behavior based on the result of FEM analysis after modeling a pipe including a joint, and pipe behavior including joint displacement and joint bending angle based on the result. Is a method and an apparatus for simply estimating the behavior of a buried pipe across a fault based on the estimation formula of the pipeline behavior.

Hereinafter, it demonstrates in order.
FIG. 2A shows the displacement distribution of the active fault disclosed by the Active Fault and Earthquake Research Center of the National Institute of Advanced Industrial Science and Technology. As of August 2014, reverse faults account for about 50%, and active fault slopes account for 90% at 45 °, 60 ° and 90 °. About half of all data is fault displacement of 2 m or less, and 3/4 is fault displacement of 3 m or less. Based on these data , a reverse fault model with an inclination of 45 °, 60 °, and 90 ° with a fault displacement of 3 m was set as an analysis target.

  In Japan, many people are concentrated in the plains and many water pipes are buried. Plains are generally formed by river sedimentation, and active faults that exist in such places are covered with sedimentary layers (alluvium), so how the sedimentary layers deform as the faults move Is important when considering the behavior of the pipeline.

  Therefore, as shown in FIG. 2 (b), the layer thickness H of the alluvium is set to 10 m, and the range of influence on the ground surface is set to the numerical value shown in the lower table of the same figure. Keita Honda et al., “Layer thickness distribution characteristics of alluvium in the Japanese archipelago” (Geographical Journal 119, pp. 924-933, 2010), and Onizuka et al. “On the deformation and stress of the ground accompanying reverse fault displacement of the basement” (Applied Mechanics Papers, Vol. 2, pp. 533-542, 1999).

  FIG. 3A shows a joint spring and ground spring model. The pipe connected by the seismic joint to be analyzed is regarded as a beam (rigid body) on the elastic floor, and the joint and the ground were modeled based on the spring constant obtained from the experiment.

  3 (b) to 3 (d) show the characteristics of the joint spring, and FIGS. 3 (e) and 3 (f) show the characteristics of the ground spring. The rotary spring of the joint spring is a joint of the inlet side pipe on the inner surface of the joint part of the inlet side pipe with the pipe axis of the inlet side pipe and the pipe axis of the inlet side pipe bent. An angle (θa in FIG. 3C, 4.9 ° at a nominal diameter 75) at which the outer surface comes into contact and is difficult to bend is set. This angle is referred to as a reference allowable bending angle α and is an angle corresponding to the nominal diameter. NS type ductile iron pipes with a nominal diameter of 75 to 250 have a maximum bending angle of 8 ° that can be bent during an earthquake, and the joint performance is maintained within 8 °. This angle is referred to as the maximum allowable bending angle β. Note that the values of the reference allowable bending angle α and the maximum allowable bending angle β are not limited to the values described in the present embodiment, and may be different values depending on the nominal diameter or different values depending on the type of the earthquake-resistant joint iron pipe. May be set.

  Axial springs have different spring constants in the region that can withstand the tensile force due to the static frictional force of the rubber ring of the joint, the region where the pipe and rubber ring slide and extend the joint, and the region where the joint pull-out prevention mechanism works to stop expansion and contraction. Is set.

  Among the ground springs, the pipe axial ground spring is set by a bilinear model in which the spring constant decreases when the relative displacement between the pipe and the ground exceeds the limit in consideration of the slip between the pipe and the ground. Is set in consideration of the ground reaction force when the pipe moves downward relative to the ground, and considering the collapse of the ground when the pipe moves upward relative to the ground. Both are set by a bilinear model in which the spring constant decreases when the relative displacement between the pipe and the ground exceeds a limit value.

Using a three-dimensional frame structure nonlinear dynamic analysis system “DYNA2E” (ITOCHU Techno-Solutions Corporation), FEM analysis was performed on such a joint spring and ground spring model by changing the fault position and pipe length. The ground condition was an alluvial sandy ground equivalent to an N value of 15, and the ground reaction force coefficient was calculated from the N value and set to 20,700 kN / m ³ . The influence of soil cover was ignored, and the behavior of the ground around the pipe was the same as that of the ground surface. In addition, it was confirmed that the pipe length was such that both ends of the pipe did not affect the pipe behavior at the fault crossing section, and the boundary condition was that the pipe end was completely constrained.

  FIG. 4A shows an analysis model near the fault. The analysis conditions are fault slope θ = 45 °, 60 °, 90 °, reverse fault with displacement V = 3.0 m, nominal diameter 75, 100, 150, 200, 250, and pipe length L is fixed (5 or 4 m). , 1/2 of the standard length, 1 m.

  FIG. 4B illustrates an analysis result when there is a joint at the boundary. The joints in the fixed-side ground in the range where the fault behavior does not affect (non-influential range) are defined as A1, A2... In the order closer to the boundary, and the joints in the ground in the fault affected range are defined as B1, B2. As for the boundary with the displacement side ground, the joints in the ground in the fault influence range are defined as C1, C2... And the joints in the displacement side ground in the non-influence range are defined as D1, D2. The bending angle of the joint n is βn, and the distances from the joints A1, B1, C1, D1 to the boundary portions are L1, L2, L3, and L4, respectively. When there is a joint at the boundary as shown in the figure, the joint at the boundary is defined as A1 (or C1), and the adjacent joint is defined as A2, B2 (or C2, D2). At this time, L1 (or L3) = 0, L2 (or L4) = L (tube length).

  FIG. 5A shows the characteristics of the tomographic displacement and the joint bending angle when L1 = 0 m and L3 = 0.5 m (the joint is located at the fixed-side boundary). Shows the characteristics of the tomographic displacement and the joint bending angle when L1 = 1.5 m and L3 = 0 m (the joint is located at the displacement side boundary). Both are the analysis results of the joint bending angle when the nominal diameter is 75, the pipe length is 2 m, and the fault position is changed with a fault inclination of 60 °. The sign of the joint bending angle represents the direction of bending. In any case, when the angle exceeds 4.9 °, the bending behavior is slowed down, the bending angle is largest when the joint exists at the boundary between the fault-affected area and the non-affected area, and the amount of fault displacement that can be absorbed is short (L3). = 2.76 m when 0). The same tendency was confirmed even when the nominal diameter, pipe length, and slope of the fault were changed. There was no joint that could bend to the maximum allowable bending angle β = 8 ° at a pipe length of 1 m at any nominal diameter or slope of the fault.

  FIG. 5 (c) shows the overall tendency of the analysis results when the amount of fault displacement is varied. It was found that the pipe line was displaced with the ground, the joint located at the boundary with the fault-affected area was greatly bent, and the tube generation stress was small.

  As shown in FIG. 6A, the pipe and the ground show the same movement until the joint bending angle reaches the reference allowable bending angle α = 4.9 °, and the joint bending angle reaches the reference allowable bending angle α = 4.9 °. Beyond that, the bending moment suddenly increased, and it was also found that a deviation occurred between the pipe and the ground. Based on the above analysis results, the pipeline behavior is geometrically modeled as follows.

As shown in FIGS. 6B and 6C, when the fault is displaced by V, the joint A1 (C1) at the boundary between the fault affected range and the non-affected range and the adjacent joints A2 (C2) and B2 ( Considering the bending angle β _A1 (β _C1 ) of the joint A1 (C1) assuming that D2) behaves geometrically following the fault displacement.

When the bending angle of the seismic joint ductile iron pipe reaches the reference allowable bending angle α (4.9 ° in the case of nominal diameter 75), the pipe comes into contact with the inside of the joint portion and is difficult to bend. Therefore, for example, when the nominal diameter is 75, the pipe and the ground move in the same way until β _A1 (or β _C1 ) reaches 4.9 °, but if it exceeds 4.9 °, the joint A1 (or C1) It is considered that relative displacement occurs without following the movement of the ground, and the adjacent joints A2 and B2 (or C2 and D2) begin to bend.

  Assuming that the relative displacement amount δj (j = A1, C1) between the pipe and the ground is proportional to the fault displacement excess amount δ after the reference allowable bending angle α, the proportional constant was used to calculate the following equation. This proportionality constant represents the ease of movement of the joint at the boundary, and is referred to herein as “displacement influence”.

δ _A1 = k _A1 · δ
δ _C1 = k _C1 · δ
Where δ _A1 is the amount of displacement of the joint A1, δ _C1 is the amount of displacement of the joint C1, δ is the amount of fault displacement excess after the joint bending angle reaches the reference allowable bending angle α, and k _A1 and k _C1 are the degree of displacement influence. It is. As will be described later, the displacement influence degrees k _A1 and k _C1 are calculated so that the correlation with the analysis result increases for each nominal diameter, pipe length, and slope of the fault, and the behavior is safer than the analysis result. .

When the displacement influence degree k value is determined, the coordinates of the joint A1 where β _A1 ≧ 4.9 ° are obtained. If the coordinates of the joint A1 before the fault displacement are (0, 0), the coordinates (x _A1 , y _A1 ), (x _A2 , y _A2 ), (x _B2 , y _B2 ) is obtained, and the bending angle β _A1 of the joint A1 can be calculated by the following equation. The same applies to the joint C1.

FIG. 7 shows a geometric model of pipe behavior, and formulas for calculating respective coordinates (x _A1 , y _A1 ), (x _A2 , y _A2 ), and (x _B2 , y _B2 ). .

  In FIG. 8 (a), as a representative example, the analysis result of the bending angle with respect to the amount of fault displacement is indicated by a broken line with respect to the joint C1 at the boundary with the nominal diameter 75, the pipe length 2m, the fault inclination 60 °, and the displacement side ground. Has been. The number of data is 100 points for every 0.03 m of fault displacement.

  When the displacement influence degree k value is determined, the joint bending angle with respect to the fault displacement can be estimated with reference to FIG. Displacement influence degree k value is calculated using regression analysis so that the determination coefficient R2 calculated from the residual between the analysis result and the estimation result of 100 joint bending angles for every 0.03m of fault displacement is maximized. did.

  At this time, the displacement influence degree was k = 0.133, and the determination coefficient was R2 = 0.986. The estimation result of the joint bending angle with respect to the fault displacement calculated from the k value is shown by a solid line in FIG. Both agree well, confirming that the estimation by this model is valid. The displacement influence degree k value is an index indicating the ease of movement of the joint at the boundary between the fault-affected range and the non-affected range, and it is considered that there is a correlation between the bending characteristics and the ground characteristics of the joint.

  As shown in FIG. 9A, items such as the nominal diameter of the pipe, the pipe length, the position of the joint portion, and the slope of the fault as the ground characteristics can be used as the bending characteristics of the joint, and the nominal diameter P1 of the pipe (5 conditions) : Nominal diameter 75, 100, 150, 200, 250), pipe length P2 (2 conditions: standard and standard x 1/2), fault slope P3 (3 conditions: 45 °, 60 °, 90 °) and joint The displacement influence degree k value was calculated for all 60 conditions with the position P4 (2 conditions: fixed side boundary and displacement side boundary) as a representative value.

The displacement influence degree k value was calculated so that the determination coefficient R2 calculated from the residual between the analysis result and the estimation result of the joint bending angle for each fault displacement amount 0.03 m was maximized. Based on the obtained displacement influence degree k value, each item shown in FIG. 9B is set as a target variable and its category. Based on the quantification theory class I, an estimation equation for the k value is expressed as follows: Derived. FIG. 9B also shows the category score of each objective variable obtained by partially correcting the derivation result. P _ni is a coefficient of the objective variable n category i, and x _ni is 0 or 1. These are merely examples, and the categories are not limited to the items described. For example, the position of the joint portion is not limited to the fixed side and the displacement side, but can be set to a position away from the fixed side and the displacement side within the fault influence range by a predetermined distance.

  FIG. 8B shows the k value estimated by the above equation for the joint C1 at the boundary with the nominal diameter 75, the pipe length of 2 m, the fault inclination of 60 °, and the displacement side ground, as in FIG. The result of calculating the bending angle with respect to the displacement of the fault using the solid line is shown by a solid line.

  According to the analysis result, the allowable fault displacement amount, which is the fault displacement amount at the time of bending at the maximum allowable bending angle β = 8 °, is 2.76 m, whereas in the estimation using the estimation formula shown in [Equation 2], 2. Slightly short at 19m. There is a slight divergence from the analysis result, but this is because the category score for k value estimation is rounded so that the estimation is on the safe side than the analysis result, and the estimation is on the safe side. There is no particular problem in the safety evaluation of the pipeline. In addition, the estimated k value by this estimation formula was 0.125, and the determination coefficient R was 0.972.

  Thus, by using the displacement influence degree k value obtained by the estimation equation shown in [Equation 2], the fault displacement amount when the bending angle θ of the earthquake-resistant joint or the predetermined bending angle θ is obtained is obtained with high accuracy. The behavior of the earthquake-resistant joint can be estimated based on the obtained bending angle θ or the amount of fault displacement.

  As a result, it is possible to evaluate safety not only for existing pipes but also for pipes scheduled to be laid, based on whether or not the bending angle θ of the earthquake-resistant joint with respect to the assumed fault displacement is smaller than the maximum allowable bending angle β. Thus, the safety evaluation can be performed based on whether or not the fault displacement amount when the earthquake-resistant joint has a predetermined bending angle θ that is equal to or less than the maximum allowable bending angle β is smaller than the predicted fault displacement amount for a specific fault. become.

  Then, design is performed by reflecting the nominal diameter, pipe length, joint position, etc. that can ensure safety from the values obtained by varying the nominal diameter, pipe length, and joint position of such pipes. Will be able to.

That is, the method for estimating the behavior of a cross-fault buried pipe according to the present invention is a method for estimating the behavior of a cross-fault buried pipe in which a plurality of pipes are joined via an earthquake-resistant joint having a reference allowable bending angle α and a maximum allowable bending angle β. The displacement is executed when the bending angle of a part of the seismic joint in the pipe exceeds the reference allowable bending angle α due to the fault displacement, and indicates the ratio of the displacement δj of the part of the seismic joint to the excess displacement δ of the fault. The degree of influence k is estimated using the coefficients P1i and P2i of each category for at least two objective variables P1 and P2 determined based on the quantification theory class 1, k = P _1i · x _1i + P _2i · x _2i (x _1i, x _2i is 0 or 1 and the displacement influence estimating step of obtaining at), calculates a bending angle θ of the seismic joint for assumed fault displacement amount based on the displacement influence k estimated by the displacement influence estimating step, also Then, based on the displacement influence degree k obtained by the estimation formula, the earthquake resistant joint calculates a fault displacement amount having a predetermined bending angle θ that is equal to or less than the maximum allowable bending angle β, and based on the calculated bending angle θ or fault displacement amount And a seismic joint behavior estimating step for estimating the behavior of the seismic joint.

  Further, the target variable is not limited to two, and may be set as needed. At least the target variable P1 is preferably the nominal diameter of the pipe, and the target variable P2 is preferably any one of the length of the pipe, the slope of the fault, the position of the earthquake-resistant joint, or a combination thereof. Basically, if there are few objective variables, the value of the displacement influence level k becomes smaller. Therefore, even if the same assumed fault displacement amount, the bending angle θ becomes a large value.

  According to the method for estimating the behavior of the cross-fault buried pipe, the bending angle θ at any joint within the fault-affected area can be obtained, but as is clear from the analysis results, the boundary with the fault-affected area In view of the fact that the joint located at 1 is greatly bent, some of the earthquake-resistant joints are preferably specific earthquake-resistant joints located near the boundary between the fault-affected range and the non-affected range.

  Moreover, as shown in the above [Equation 1], the bending angle θ of the specific earthquake resistant joint calculated in the earthquake resistant joint behavior estimation step is the tube angle between the earthquake resistant joint adjacent to the fault influence range side and the specific earthquake resistant joint. And the difference in tube angle between the seismic joint adjacent to the non-affected range and the specific seismic joint.

  The displacement influence degree k is approximately a joint bending characteristic with respect to a fault displacement amount, which is a simulation result for a predetermined earthquake resistant joint model, and a joint bending characteristic with respect to a fault displacement amount calculated based on the displacement influence degree k of the joint with respect to the fault displacement amount. A value obtained by a regression analysis method so as to coincide is preferable.

  However, instead of the simulation result for a given seismic joint model, when an actual or reduced model pipe is buried in the sediment deposited on the simulated fault facility and a simulated fault is generated by the simulated fault facility The measurement result may be used.

  In addition, the target variable category is determined so that the bending angle θ of the earthquake-resistant joint with respect to the calculated assumed fault displacement does not exceed the maximum allowable bending angle β, or the calculated bending angle θ becomes the maximum allowable bending angle β. By determining the target variable category so that the amount of fault displacement in the case becomes the assumed fault displacement amount, it is possible to design the laying of the pipeline ensuring safety.

  In the above-described embodiment, the case where the pipe constituting the earthquake-resistant joint pipe is an NS-type ductile iron pipe is described, but any pipe other than NS-type ductile iron pipe can be used as long as a plurality of pipes are joined via the earthquake-resistant joint. The present invention can also be applied to any steel pipe. Furthermore, the present invention can be applied to all pipe lines in which a plurality of pipes are joined via an earthquake-resistant joint having a reference allowable bending angle α and a maximum allowable bending angle β.

Hereinafter, a cross-fault buried pipe behavior estimation apparatus using the above-described cross-fault buried pipe behavior estimation method will be described.
As shown in FIG. 10, the behavior estimation apparatus 100 for a cross-fault buried pipeline is configured by a handheld computer and includes a touch panel type liquid crystal display unit 10, a storage unit 30, and calculation units 20 and 40.

  The storage unit 30 stores objective variables and coefficients for each category for calculating the above-described displacement influence degree k value based on [Equation 2]. Specifically, the nominal diameter, the pipe length, the slope of the fault, the position of the joint portion, and the coefficients for them described in FIG. 9B are stored. In addition, the objective variable and the kind and number of each category are examples, and are not limited to these.

  The liquid crystal display unit 10 is provided with an input unit 11 on which a software switch is displayed. By operating the switch displayed on the screen, a behavior estimation process of a cross-fault buried pipeline is executed, and the result is displayed on the display unit. 12 is displayed.

  The target variable and category stored in the storage unit 30 are displayed in the input unit 11, and the k value estimation condition is determined by selecting and operating the selected variable. Further, either the assumed bending angle θ or the assumed fault displacement amount is determined. When the assumed fault displacement amount is set and inputted, the bending angle θ of the joint when the fault of the assumed fault displacement is activated is calculated, and when the assumed bending angle is set and inputted, the joint portion A tomographic displacement amount when the assumed bending angle is bent is calculated.

In the calculation unit, first, the displacement influence degree estimation calculation unit 20 reads out the coefficient of the target variable category input from the input unit 11 from the storage unit 30, and calculates the displacement influence degree k from the estimation equation k = P _1i · x _1i + P. _2i · x _2i (where x _1i and x _2i are 0 or 1).

  Next, the earthquake-resistant joint behavior estimation calculation unit 40 calculates the bending angle θ of the earthquake-proof joint with respect to the assumed fault displacement based on the displacement influence degree k calculated by the displacement influence degree estimation calculation unit 20, or is obtained by an estimation formula. Based on the obtained displacement influence degree k, the fault displacement amount at which the seismic joint has a predetermined bending angle θ equal to or less than the maximum allowable bending angle β is calculated.

  FIG. 11 shows an operation flow of the behavior estimation device for a fault crossing buried pipeline. First, when the objective variable and each category relating to the fault, ground, and pipeline, which are the evaluation conditions, are set via the input unit 11 (S1), the displacement influence degree estimation calculating part 20 calculates the displacement influence degree k value. (S2) Each pipe position coordinate is calculated by the earthquake-resistant joint behavior estimation calculation unit 40 (S3), and further, the joint bending angle is calculated and displayed on the display unit 12 (S4).

  As a result, if the operator can determine that the safety is sufficiently secured, the process is terminated (S5). If not, for example, the category of the tube length is changed and set (S6). The calculation process is repeated.

  The bending angle θ or the fault displacement excess amount δ calculated by the earthquake-resistant joint behavior estimation calculation unit 40 is displayed on the display unit 12, and the safety evaluation can be performed by confirming the behavior of the earthquake-resistant joint based on the displayed value. become.

  Therefore, a cross-fault buried pipe behavior estimation method and a cross-fault buried pipe behavior estimation apparatus that can easily obtain accuracy can be realized without using a dedicated large-scale analysis device.

  The above description is an explanation of one embodiment of the behavior estimation method of the cross-fault buried pipeline and the behavior estimation apparatus of the cross-fault buried pipeline, and the scope of the present invention is not limited by the description, and the target variable The coefficients of the target variable category are not limited to the types and values described above, and it is needless to say that the design can be appropriately changed within the range where the effects of the present invention are exhibited.

1: Tube 10: Display device 11: Input unit 12: Display unit 20: Displacement influence degree estimation calculation unit 30: Storage unit 40: Seismic joint behavior estimation calculation unit 100: Cross-fault buried pipe behavior estimation device

Claims (7)

A method for estimating the behavior of a cross-fault buried pipeline in which a plurality of pipes are joined via an earthquake-resistant joint having a reference allowable bending angle α and a maximum allowable bending angle β,
Beyond bending angle of a portion of the seismic joint before SL line is the reference allowable bending angle α is the limit to bend to follow the movement of the ground caused by fault displacement, if you displaced relative movement of the ground A displacement influence degree k indicating the ratio of the displacement amount δj of the partial seismic joint to the fault displacement excess amount δ, which is the fault displacement amount after being executed and reaching the fault displacement amount reaching the reference allowable bending angle α , Estimated expression k = P _1i · x _1i + P _2i · x _2i (x _1i , x _2i is the coefficient P1i, P2i of each category for at least two objective variables P1 and P2 determined based on the quantification theory class 1 0 or 1)
The displacement influence degree estimation step obtained in
Wherein calculating the bending angle θ is a behavior of seismic joint for assumed fault displacement amount based on the displacement influence k estimated by the displacement influence estimating step, for the assumed fault displacement amount based on the bending angle θ which issued calculated Fault displacement that makes it possible to evaluate the safety of a seismic joint , or the behavior of a seismic joint has a predetermined bending angle θ that is less than or equal to the maximum allowable bending angle β based on the displacement influence degree k estimated in the displacement influence degree estimation step A seismic joint behavior estimation step capable of calculating the amount, and evaluating the safety of the seismic joint with respect to the bending angle θ based on whether the calculated fault displacement amount is smaller than the predicted fault displacement amount ;
Only including,
The P1 is a nominal diameter of a pipe, and the P2 is a method for estimating a behavior of a cross-fault buried pipe, which is any one or a combination of a pipe length, a fault inclination, and a position of a seismic joint . It said portion of the seismic joint specific seismic joint at which claim 1 behavior estimation method of fault transverse buried duct according positioned in the vicinity of the boundary between the fault influence range and the non-affected area. The bending angle θ of the specific seismic joint calculated in the earthquake-resistant joint behavior estimation step includes the tube angle between the seismic joint adjacent to the fault-affected area and the specific seismic joint, and the seismic joint adjacent to the non-affected area side. The method for estimating the behavior of a cross-fault buried pipe according to claim 2, which is obtained from a difference between the pipe angle and the specified earthquake-resistant joint. The displacement influence degree k is approximately a joint bending characteristic with respect to a fault displacement amount, which is a simulation result for a predetermined earthquake resistant joint model, and a joint bending characteristic with respect to a fault displacement amount calculated based on the displacement influence degree k of the joint with respect to the fault displacement amount. The method for estimating the behavior of a cross-fault buried pipe according to any one of claims 1 to 3 , which is a value obtained by a regression analysis method so as to match. Obtain the target variable category so that the bending angle θ of the seismic joint with respect to the calculated assumed fault displacement does not exceed the maximum allowable bending angle β, or when the calculated bending angle θ is the maximum allowable bending angle β The method for estimating the behavior of a cross-fault buried pipeline according to any one of claims 1 to 4 , wherein a category of a target variable is obtained so that the fault displacement amount becomes an assumed fault displacement amount. The method for estimating the behavior of a fault-crossing buried pipe according to any one of claims 1 to 5 , wherein the pipe is a seismic joint ductile iron pipe. A device for estimating the behavior of a cross-fault buried pipe in which a plurality of pipes are joined via an earthquake-resistant joint having a reference allowable bending angle α and a maximum allowable bending angle β,
A storage unit for storing coefficients P1i and P2i of each category for at least two objective variables P1 and P2 determined based on the quantification theory class 1,
An input unit for selectively inputting a category of the objective variable stored in the storage unit;
Bending angle of the part of the seismic joint exceeds the reference allowable bending angle α is the limit to bend to follow the movement of the ground by the fault displacement is executed when you displaced relative movement of the ground,
The coefficient of the target variable category input at the input unit is read from the storage unit, and the one with respect to the fault displacement excess amount δ which is the fault displacement amount after reaching the fault displacement amount reaching the reference allowable bending angle α. The displacement influence degree k indicating the ratio of the deviation amount δj of the seismic joint of the portion is estimated by the equation k = P _1i · x _1i + P _2i · x _2i (x _1i , x _2i is 0 or 1)
A displacement influence degree estimation calculation unit obtained in
Wherein calculating the bending angle θ of the seismic joint against displacement influence estimating assumed fault displacement amount based on the calculated displacement influence k in the calculating portion, seismic joint with respect to the assumed fault displacement amount based on the bending angle θ which issued calculated of safety to enable evaluation, or the fault displacement amount of behavior is the maximum allowable flexion angle β below the predetermined bending angle θ seismic joint on the basis of the displacement influence estimating displacement influence k estimated in step An earthquake-resistant joint behavior estimation calculation unit that can calculate and evaluate safety of the earthquake-resistant joint with respect to the bending angle θ based on whether the calculated fault displacement amount is smaller than the predicted fault displacement amount ;
A display unit for displaying a calculation result by the earthquake-resistant joint behavior estimation calculation unit;
Only including,
The P1 is a nominal diameter of a pipe, and the P2 is a behavior estimation device for a cross-fault buried pipe, which is any one or a combination of a pipe length, a fault inclination, and a position of a seismic joint .