JP6362031B2 - Displacement adjustment method and jack control system in underpinning - Google Patents

Description

  The present invention relates to a displacement adjustment method and jack control system in underpinning applied when an underground structure is constructed by an underpinning method.

  When constructing underground structures in the underground space, change the load of the existing structures so that the existing structures such as buildings and viaducts built on the ground will not be affected. Underpinning methods are used, but underground structures such as road tunnels and railway tunnels are often built in urban areas. In such cases, these underground structures are also installed. Since it is necessary to replace the load as a structure, the underpinning method requires higher reliability and safety.

  To construct an underground structure using the underpinning method, exchanging the load of the existing structure with a temporary receiving girder and excavating the lower part of the existing structure to form a new underground structure However, the load acting on the temporary support girder varies daily with the progress of the construction work due to a decrease in the reaction load caused by excavation.

  Therefore, a jack is arranged between the existing structure and the temporary support beam, and the vertical displacement of the existing structure is measured while monitoring whether the measured value does not deviate from the management width. If there is a concern over the width, the vertical displacement is adjusted by operating the jack so that the vertical displacement is offset.

Japanese Patent Laid-Open No. 2004-150151 JP 2004-107971 A JP 2014-92008 Publication

  However, in the method described above, even if the displacement of the existing structure is adjusted by operating the jack at a certain time, it may be necessary to readjust immediately thereafter, and the vertical displacement of the existing structure may be reduced during the construction period. The problem was that there was a need to adjust frequently.

  In addition, when performing construction continuously for each section along the horizontal direction, when performing adjustment operations in the section to be excavated, an attempt is made to make the vertical displacement smoothly change from the preceding section adjacent to that section. Then, there also arises a problem that readjustment may be required immediately in the preceding section.

  Furthermore, the displacement adjustment of the existing structure is basically performed so that the measured value does not deviate from the management width, so that the vertical displacement of the existing structure changes for a long time at a value close to the upper limit or lower limit of the management width. In some cases, there was a problem that the quality was not so desirable.

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a displacement adjustment method and jack control system in underpinning that can reduce the adjustment frequency of vertical displacement generated in an existing structure. To do.

  Another object of the present invention is to provide a displacement adjustment method and jack control system in underpinning that can adjust the vertical displacement of an existing structure with a sufficient margin with respect to the management width.

In order to achieve the above object, a displacement adjustment method in underpinning according to the present invention, as described in claim 1, receives a load of an existing structure sequentially along a horizontal direction and for each section along the direction. In the displacement adjustment method in underpinning for adjusting the vertical displacement of the existing structure when constructing an underground structure below the existing structure while changing,
Of the sections, the section to be excavated is the first section, the section adjacent to the first section and excavated in advance of the section is the second section, and the second section is the second section. A section that is adjacent on the opposite side of section 1 and that has been excavated prior to the first section and the second section is defined as a third section, and after the start of excavation in the first section The time history vertical displacement of the existing structure is calculated as an estimated vertical displacement at a plurality of support points provided in the existing structure to replace the load of the existing structure located in the section,
The time when the difference between the maximum value and the minimum value in each estimated vertical displacement first exceeds the allowable range is calculated as the limit time,
Among the limit times, the earliest limit time is specified as the earliest limit time,
The maximum value of each estimated vertical displacement up to the earliest limit time is less than the upper limit of the management width and the minimum value is greater than or equal to the lower limit of the management width.
The vertical displacement of the existing structure in the first section when each of the temporary adjustment displacements is applied to each of the support points smoothly continues with the vertical displacement of the existing structure in the third section. As described above, the displacement to be applied to the existing structure in the second section is obtained as a provisional auxiliary adjustment displacement,
The provisional auxiliary adjustment displacement is obtained by the series of steps when the second section is an object to be excavated when it is applied to the second section at the start of excavation of the first section. The maximum value of each estimated vertical displacement at the plurality of support points provided in the existing structure in the second section does not exceed the upper limit of the management width and is the minimum before the earliest limit time in the second section arrives When the value does not fall below the lower limit of the management width, the provisional adjustment displacement and the provisional auxiliary adjustment displacement are set as adjustment displacement and auxiliary adjustment displacement, respectively.
The provisional auxiliary adjustment displacement is applied to the second section at the start of excavation in the first section, and the second section has a maximum time until the earliest time limit for the second section arrives. When the maximum value of each estimated vertical displacement exceeds the upper limit of the management width or the minimum value is lower than the lower limit of the management width, each estimation in the second section until the earliest limit time for the second section arrives. Each estimated vertical in the first interval until the earliest limit time for the first interval arrives so that the maximum value of the vertical displacement does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width. The maximum value of displacement does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width, and the existing structures in the first section, the second section, and the third section The vertical displacement is continued smoothly. With the auxiliary shift displacement by modifying the constant auxiliary shift displacement, and adjusts the displacement and correct the provisional adjustment displacement,
The adjustment displacement is applied to the support points in the first section at the start of excavation in the first section, and the auxiliary adjustment displacement is applied to the support points in the second section.

  In the displacement adjustment method in underpinning according to the present invention, the adjustment displacement that does not correspond to the earliest limit time in the first section or the auxiliary adjustment displacement among the adjustment displacements up to the earliest limit time. Each of the median values of the maximum value and the minimum value of the estimated vertical displacement is determined to be the median value of the management width.

According to a third aspect of the present invention, there is provided a jack control system for underpinning in order to receive the load of an existing structure sequentially along a horizontal direction and for each section along the direction. In the jack control system in underpinning, comprising jacks respectively installed at a plurality of support points for each section provided in a structure, and arithmetic control means for operating each jack,
Among the sections, the arithmetic and control means is configured such that a section to be excavated is a first section, a section adjacent to the first section and excavated in advance of the section is a second section, the second section A section that is adjacent to the second section on the opposite side of the first section and that has been excavated prior to the first section and the second section is a third section, and the first section Estimated vertical displacement of the time history of the existing structure after excavation in the section at a plurality of support points located in the existing structure to receive the load of the existing structure located in the section The time when the difference between the maximum value and the minimum value in each estimated vertical displacement first exceeds the allowable range is calculated as the limit time, and the earliest limit time of the limit times is the earliest limit time. And each estimated lead up to the earliest limit time The displacement to be adjusted at the start of excavation is determined as a provisional adjustment displacement so that the maximum value of the displacement is less than or equal to the upper limit of the management width and the minimum value is greater than or equal to the lower limit of the management width. In the second section, the vertical displacement of the existing structure in the first section when added to the first section is smoothly continued with the vertical displacement of the existing structure in the third section. A displacement to be applied to an existing structure is obtained as a provisional auxiliary adjustment displacement, and the provisional auxiliary adjustment displacement is applied to the second section at the start of excavation in the first section, and the second section A plurality of supports provided in the existing structure in the second section until the earliest limit time in the second section is obtained by the series of steps when the object is an excavation target. When the maximum value of each estimated vertical displacement at the point does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width, the temporary adjustment displacement and the temporary auxiliary adjustment displacement are adjusted displacement and auxiliary adjustment displacement, respectively. The provisional auxiliary adjustment displacement is applied to the second section at the start of excavation of the first section, and the second limit time is reached before the earliest limit time for the second section arrives. In the case where the maximum value of each estimated vertical displacement in the section exceeds the upper limit of the management width or the minimum value is lower than the lower limit of the management width, in the second section until the earliest limit time for the second section arrives In order that the maximum value of each estimated vertical displacement does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width, each of the first intervals until the earliest limit time of the first section arrives. The maximum estimated vertical displacement is The vertical displacement of the existing structure in the first section, the second section, and the third section is smooth so that the upper limit of the management width is not exceeded and the minimum value does not fall below the lower limit of the management width. The temporary auxiliary adjustment displacement is corrected to be an auxiliary adjustment displacement so as to be continuous, and the temporary adjustment displacement is corrected to be an adjustment displacement.
Among the jacks, the adjustment displacement is generated at the support point in the first section at the start of excavation in the first section, and the auxiliary adjustment displacement is generated at the support point in the second section. At least one is configured to be operable.

  Further, the jack control system in the underpinning according to the present invention may be configured such that the calculation control means includes the adjustment displacement not corresponding to the earliest limit time in the first section or the auxiliary adjustment displacement among the adjustment displacements. The median value between the maximum value and the minimum value of the estimated vertical displacement up to the earliest limit time is determined so as to be the median value of the management width.

In the jack control system for underpinning according to the present invention, the arithmetic control means may be configured such that a unit amount of jack stroke is provided at a support point Ri (i = 1, 2,... N) among the support points. A vertical displacement generated at each of the support points Rj (j = 1, 2,... N) at a given time is calculated for each of the support points and an influence coefficient fij (i = 1, 2,... N , j = 1, 2,... N), and the inverse matrix of the matrix [F] having the influence coefficient as an element is calculated as [F] ⁻¹ , and includes the adjustment displacement and the auxiliary adjustment displacement. Assuming that the total adjustment displacement is {δ},
{S} = [F] ⁻¹ {δ}
By calculating the operation amount of each jack as the required stroke amount {s} (si (i = 1, 2,... N)).

  The jack control system for underpinning according to the present invention includes vertical displacement measuring means for measuring the vertical displacement of the existing structure at each of the support points.

  In order to reduce the vertical displacement adjustment frequency in existing structures when underpinning work is performed, adjust the vertical displacement each time the vertical displacement of the existing structure actually fluctuates. Rather than calculating the time history vertical displacement of the existing structure after the start of excavation as an estimated vertical displacement, the future prediction is made, and then the adjustment so that the fluctuation of the estimated vertical displacement stays within the control range for as long as possible. What is necessary is just to specify a displacement and give this to an existing structure beforehand at the time of a digging start.

  However, when construction is performed continuously for each section along the horizontal direction, for example, when a tunnel is constructed along the material axis direction directly below the embankment or viaduct where the train track is laid, the vertical of the existing structure In adjusting the displacement, the single adjustment for each section is not sufficient, and the adjusted vertical displacement needs to be smoothly continued over the adjacent sections.

  Therefore, the vertical displacement of the existing structure in the preceding section must be readjusted. In this case, the adjustment operation is first performed in the preceding section by applying the adjustment displacement when the preceding section is the excavation target section. Even if it is extended, depending on the result of readjustment, there may occur a situation where the adjustment operation cannot be delayed until the postponement time due to the original adjustment displacement.

  In order to delay the adjustment operation of the vertical displacement until the protracted time due to the original adjustment displacement given in the preceding section, in order to smoothly continue the vertical displacement after adjustment in the existing structure over the adjacent sections, the present invention It was made with a focus on how to do it.

  That is, in the displacement adjustment method and jack control system in underpinning according to the present invention, the load of the existing structure is changed while sequentially receiving the load of the existing structure along the horizontal direction and for each section along the direction. When adjusting the vertical displacement of the existing structure when constructing the underground structure below, first of all the above-mentioned sections, the section to be excavated is set as the first section, and after the start of excavation in the section The time history vertical displacement of the existing structure is calculated as the estimated vertical displacement.

  The calculation of the estimated vertical displacement is performed at each of a plurality of support points located in the first section provided in the existing structure in order to exchange the load of the existing structure.

  The section adjacent to the first section and excavated prior to the section is the second section, the second section is adjacent to the opposite side of the first section, the first section and the second section The section where excavation was performed prior to section 2 is defined as the third section.

  Next, the time when the difference between the maximum value and the minimum value in each estimated vertical displacement first exceeds the allowable range is calculated as the limit time.

  Here, the time when the difference between the maximum value and the minimum value in each estimated vertical displacement first exceeds the allowable width is the minimum value of the vertical displacement of the existing structure reaching the lower limit of the management width by the timing at the latest. It means that the upper limit of the management width is reached as the maximum value, and if no adjustment is made, the vertical displacement of the existing structure will be managed before reaching the limit time, possibly just after the start of excavation. It is assumed that the lower limit of the width is reached or the upper limit of the management width is reached.

  Therefore, in the present invention, the following steps are continued.

  After the limit time is calculated as described above, the limit time that arrives earliest among these limit times is specified as the earliest limit time.

  Next, obtain the displacement to be adjusted at the start of excavation as a provisional adjustment displacement so that the maximum value of each estimated vertical displacement up to the earliest limit time is less than the upper limit of the management width and the minimum value is more than the lower limit of the management width. .

  Next, the vertical displacement of the existing structure in the first section when each of the provisional adjustment displacements described above is applied to each of the support points causes the vertical displacement of the existing structure in the third section through the second section. A displacement to be applied to the existing structure in the second section is obtained as a temporary auxiliary adjustment displacement so as to be smoothly continuous with the vertical displacement. In the third section, no adjustment is performed.

Next, when the temporary auxiliary adjustment displacement is applied to the second section at the start of excavation of the first section, the following case classification is performed. That is,
(a) It is provided in the existing structure in the second section until the earliest limit time in the second section obtained by the above-described series of steps when the second section is an excavation target. If the maximum value of each estimated vertical displacement at multiple support points does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width, the above-mentioned temporary adjustment displacement and temporary auxiliary adjustment displacement are adjusted respectively. Displacement and auxiliary adjustment displacement.

(b) On the other hand, when the maximum value of each estimated vertical displacement in the second section exceeds the upper limit of the management width or the minimum value is lower than the lower limit of the management width by the earliest limit time for the second section Includes the following three conditions (b-1), (b-2), and (b-3):
(b-1) Until the earliest limit time for the second section arrives, the maximum value of the estimated vertical displacement in the second section does not exceed the upper limit of the management width, and the minimum value does not fall below the lower limit of the management width
(b-2) Until the earliest limit time for the first section arrives, the maximum value of each estimated vertical displacement in the first section does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width
(b-3) Auxiliary adjustment displacement is corrected by correcting the above-mentioned provisional auxiliary adjustment displacement so that the vertical displacement of the existing structure in the first, second and third intervals continues smoothly. In addition, the provisional adjustment displacement described above is corrected to be an adjustment displacement.

  Next, at the start of excavation in the first section, adjustment displacement is applied to each support point in the first section, and auxiliary adjustment displacement is applied to each support point in the second section.

  As described above, after obtaining the adjustment displacement and the auxiliary adjustment displacement, the adjustment displacement is generated at the support point in the first section and the auxiliary adjustment displacement is generated at the support point in the second section at the start of excavation in the first section. If the jack is operated as described above, in the first section and the second section, the vertical displacement of the existing structure is below the lower limit of the management width or exceeds the upper limit by the earliest limit time in each section. Absent.

  Therefore, while ensuring the smooth continuity of the vertical displacement of the existing structure over adjacent sections, the vertical generated in the existing structure not only in the first section to be excavated but also in the second section to be re-corrected. It becomes possible to delay the next adjustment time of the displacement as much as possible, and thus the frequency of adjusting the vertical displacement generated in the existing structure during the construction period can be greatly reduced.

  The allowable width may be the same as the width of the management value, but the management width may be multiplied by a reduction factor, that is, a numerical value such as 0.9, 0.8.

  The estimated vertical displacement may be appropriately predicted and analyzed based on a change in the situation according to the progress of the construction, or the prediction analysis may be performed in real time on the site, or the result of the prediction analysis in advance may be used locally. .

  The temporarily calculated temporary adjustment displacement and the final adjustment displacement are related to the first section, and are the values at the support point corresponding to the earliest limit time (hereinafter referred to as critical support point). There are two types of values at other support points (hereinafter, non-critical support points), but at critical support points, the maximum estimated vertical displacement is equal to the upper limit of the management width, and the minimum value is the lower limit of the management width. Therefore, there is no adjustment fee for changing the value. Therefore, at the critical support point, the provisional adjustment displacement becomes the adjustment displacement as it is.

  On the other hand, the temporary auxiliary adjustment displacement that is temporarily calculated and the auxiliary adjustment displacement that is the final value are related to the second section, and are similar to the values at the critical support point as in the first section. There are two types of values at the critical support point. At the critical support point, the maximum estimated vertical displacement is equal to the upper limit of the management width, and the minimum value is equal to the lower limit of the management width. At the point in time, the adjustment margin for changing the value is generated upward or downward in the second section with the passage of time. Therefore, even at the critical support point, the temporary auxiliary adjustment displacement and the auxiliary adjustment displacement can take different values.

  The adjustment displacement at the non-critical support point in the first section, that is, the adjustment displacement not corresponding to the earliest limit time in the first section and the auxiliary adjustment displacement in the second section are estimated vertical to the earliest limit time in each section. As long as the maximum value of the displacement is not more than the upper limit of the management width and the minimum value is not less than the lower limit of the management width, how to set is arbitrary, but the maximum and minimum values of the estimated vertical displacement described above If the respective values are determined so that the median of the above becomes the median of the management width, the adjustment displacement and the auxiliary adjustment displacement described above can be accommodated within the management width with a margin.

The jack may be operated in any way as long as adjustment displacement occurs in the first section and auxiliary adjustment displacement occurs in the second section at the start of excavation in the first section. The control means controls the support points Rj (j = 1, 2) when a jack stroke of a unit amount is given to a support point Ri (i = 1, 2,... N) among the support points. ,... N) are calculated for each of the support points to obtain an influence coefficient fij (i = 1, 2,... N, j = 1, 2,... N) and The inverse matrix of the matrix [F] having the influence coefficient as an element is calculated as [F] ⁻¹ , and the overall adjustment displacement including the adjustment displacement and the auxiliary adjustment displacement described above as {δ},
{S} = [F] ⁻¹ {δ}
Can be configured to calculate the operation amount of each jack as the required stroke amount {s} (si (i = 1, 2,... N)).

  In this way, it is possible to reliably generate the adjustment displacement in the first section and the auxiliary adjustment displacement in the second section.

  In the present invention, the basis of the calculation is the estimated vertical displacement at the support point of the existing structure and not the actual measurement value. Therefore, it is not always necessary to measure the vertical displacement of the existing structure. Since the estimated vertical displacement can be corrected using the measurement result by the vertical displacement measuring means if the vertical displacement measuring means for measuring each of the supported points is provided, the calculation accuracy of the adjustment displacement and the auxiliary adjustment displacement, As a result, the adjustment accuracy of the vertical displacement in the existing structure can be greatly increased.

The flowchart which showed the implementation procedure of the displacement adjustment method in the underpinning which concerns on this embodiment. It is the structure schematic to which the above-mentioned displacement adjustment method is applied, (a) is a side view seen from the bridge axis orthogonal direction of viaduct 2, (b) is a vertical sectional view along the AA line. The block diagram of the jack control system 1 in the underpinning which concerns on this embodiment. Schematic which showed the correction area, the correction assistance area, and the non-correction area in relation to the excavation status of the ground 3. A graph in which the estimated vertical displacements δ _E , δ _F and δ _G at the support point E, the support point F, and the support point G are plotted with the time T on the horizontal axis and the excavation start time in the correction section as T ₁ . The graph which showed the calculation procedure of temporary adjustment displacement. The change in the vertical displacement of the viaduct 2 at each support point when each temporary adjustment displacement of the support points E, F, G is added to each support point at time T ₁ when the excavation starts in the correction section is shown. Figure. The graph which showed the time change of the vertical displacement in a correction auxiliary section. The graph which showed the procedure which reviews the temporary auxiliary adjustment displacement given to the support points C and D and the temporary adjustment displacement given to the support points E and F. The graph which showed how to review the provisional auxiliary adjustment displacement and the provisional adjustment displacement.

  Embodiments of a displacement adjustment method and jack control system in underpinning according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a flowchart showing an implementation procedure of a displacement adjustment method in underpinning according to the present embodiment, FIG. 2 is a schematic diagram of a structure to which the above displacement adjustment method is applied, and FIG. 3 is a diagram showing the above displacement adjustment method. It is the block diagram which showed the jack control system 1 in the underpinning for implementing.

  As shown in FIG. 2, the jack control system 1 according to the present embodiment uses the viaduct 2 as an existing structure to be replaced, and loads the viaduct to the temporary receiving piles 4 and 4 constructed on the ground 3 and the temporary bridge. It is applied to the underpinning method of constructing a new underground structure 6 below the temporary support beam 5 while receiving it with a replacement structure consisting of the temporary reception beam 5 bridged over the receiving pile. The replacement is performed sequentially along the horizontal bridge axis direction of the viaduct 2 and for each section along the direction, and as shown in FIG. As a plurality of hydraulic jacks 7 arranged between the temporary support beam 5 so as to support the viaduct, a displacement meter 8 as a vertical displacement measuring means for measuring the vertical displacement of the viaduct 2, and an arithmetic control means An arithmetic processing unit 13 and a control unit 9, By controlling the driving of the hydraulic jack 7 in parts, and is capable of adjusting the vertical displacement of the viaduct 2 at each support point mentioned above, to retain the high-bridge to a desired position and orientation thus.

  The arithmetic processing unit 13 can be composed of hardware such as a CPU, a mother board, and a memory constituting the personal computer 12 and software operating on the hardware, and the personal computer 12 stores storage means for storing various data. As a hard disk 10 and a display 11.

  The displacement meter 8 is installed on the lower surface of the underground beam constituting the viaduct 2 and in the vicinity of the hydraulic jack 7, and with this configuration, the vertical displacement of the viaduct 2 with the installation position of the hydraulic jack 7 as a supporting point is detected. It can be measured.

  The control unit 9 can adjust the vertical displacement of the viaduct 2 by driving and controlling each hydraulic jack 7 so that the adjustment displacement and the auxiliary adjustment displacement described later calculated by the arithmetic processing unit 13 are generated. .

  Next, a procedure for adjusting the displacement of the viaduct 2 using the jack control system 1 according to the present embodiment will be described.

  In the following description, as shown in FIG. 2 (a), the area extending just below the viaduct 2 in the ground 3 is uncorrected as a third section along the horizontal bridge axis direction of the viaduct 2. It is divided into three sections, a correction auxiliary section as the second section, and a correction section as the first section, and the replacement is performed in the order of these. In the same figure, it moves from left to right, and in the state before the time depicted in the figure, the non-correction section is the correction auxiliary section, the correction auxiliary section is the correction section, In the state after the time depicted in the figure, the correction auxiliary section is the non-correction section, the correction section is the correction auxiliary section, and the section located on the right side of the correction section is the correction section, In these cases, the following description applies similarly.

  FIG. 4 newly shows each section shown in FIG. 2 (a) by paying attention to the excavation status of the ground 3. As can be seen clearly in FIG. 4, the corrected section is a section to be excavated. Therefore, it is positioned as a section for correcting the fluctuation of the vertical displacement of the viaduct 2 due to the load change during excavation. The correction auxiliary section is adjacent to the correction section and excavated prior to the section, and the non-correction section is adjacent to the correction auxiliary section on the opposite side of the correction section and the correction section and the correction auxiliary section. Is a section where excavation has been performed prior to, but the correction auxiliary section is a correction section that needs to be corrected due to a load change due to excavation, and an uncorrected section that should not be corrected because excavation has ended The vertical displacement of the viaduct 2 is smoothly and continuously played between the two.

  In order to adjust the displacement of the viaduct 2 using the jack control system 1 according to the present embodiment, first, the time history vertical displacement of the viaduct 2 after the start of excavation in the correction section is calculated as the estimated vertical displacement (FIG. 1, step). 101).

  Estimated vertical displacement is calculated at a plurality of support points located in the correction section provided on the viaduct to receive the load of the viaduct 2, and at the three support points in the example shown in FIG. 2 (a). Do. In the following description, a total of seven support points by the temporary support piles 4 and 4 and the temporary support beam 5 shown in FIG. 2 (a) are shown in order from the left, A, B, C, D, E, F, G, and the two support points located in the non-correction section are the support point A and the support point B, and the two support points located in the correction auxiliary section are the support point C, the support point D, and the correction point described above. These three support points are referred to as support point E, support point F, and support point G.

FIG. 5 shows the estimated vertical displacements δ _E , δ _F and δ _G at the support point E, the support point F, and the support point G, the time T on the horizontal axis, and the excavation start time in the correction section as T _1. It is drawn.

As can be seen from the graph drawn in the figure, the estimated vertical displacement δ _E at the support point E generally decreases with time, and after taking the maximum value δ _max after the start of excavation, the minimum value δ _min is updated one after another. Is done.

Support points F, a putative vertical displacement [delta] _F and [delta] _G is also the same tendency in the support point G, after taking the maximum value [delta] _max immediately after the start of excavation, one after another minimum value [delta] _min with time updating Is done.

  Such fluctuation tendency of the estimated vertical displacement is excavated below the temporary support beam 5 while receiving the load of the viaduct 2 with the above-described replacement structure composed of the temporary support piles 4 and 4 and the temporary support beam 5. At this time, as the excavation progresses, the reaction force from the excavated ground is reduced, and the temporary girder 5 can be observed to bend more greatly.

The estimated vertical displacement is, for example, based on the change in the situation according to the progress of the construction, in the above example, the prediction analysis is performed in consideration of the reaction force decrease accompanying the progress of excavation, and the prediction result is stored in the hard disk 10 In addition, the vertical displacement of the viaduct 2 at time T ₁ when excavation is started is measured by the displacement meter 8 and combined with the prediction result read from the hard disk 10 as an initial value, the time T ₁ It can be calculated as a time variation from

  Next, the time when the difference between the maximum value and the minimum value in each estimated vertical displacement first exceeds the allowable range is calculated as the limit time (FIG. 1, step 102).

  As a calculation procedure, the arithmetic processing unit 13 defines two variables for storing two numerical values, compares the value of each variable with the estimated vertical displacement, and sets one of the two variables. If the estimated vertical displacement is greater than the stored value, store the value in one variable newly, and if the estimated vertical displacement is smaller than the value stored in the other variable, enter the value. By repeating the operation of newly storing in the other variable at a constant time interval Δt, the maximum value from the start of excavation in the correction section is held in one variable, the minimum value is held in the other variable, and the maximum value And the minimum value are calculated for each time increment Δt. When the difference exceeds the allowable width Δ, the calculation is stopped repeatedly and the time at that time is stored in the hard disk 10 as the limit time.

In the example of FIG. 5, the estimated vertical displacement [delta] _E at the support points E, after taking the maximum value [delta] _max after the start excavation, over time while updating the minimum value [delta] _min, then the maximum value [delta] _max The difference from the minimum value δ _min first exceeds the allowable width Δ at time T _E.

Therefore, for the estimated vertical displacement [delta] _E at the support points E, the time T _E is the limit time.

Further, the estimated vertical displacement [delta] _G at the support point G, after taking the maximum value [delta] _max at the start excavation, over time while updating the minimum value [delta] _min, then the maximum value [delta] _max and the minimum value [delta] _min The difference with the first exceeds the allowable width Δ at time T _G.

Therefore, for the estimated vertical displacement [delta] _G at the support point G, time T _G is the limit time.

  The allowable width Δ can be set to be the same as the vertical displacement management width at each support point. For example, if the upper and lower limits of the management width are ± 10 mm, the management width is 20 mm. Δ is 20 mm. Hereinafter, in the present embodiment, it is assumed that the allowable width Δ matches the management width.

On the other hand, the estimated vertical displacement [delta] _F at the support point F, after taking the maximum value [delta] _max immediately after the start of excavation, the time while updating the minimum value [delta] _min has elapsed, then the time range shown in FIG. The difference between the maximum value δ _max and the minimum value δ _min does not exceed the allowable width Δ. Therefore, for the estimated vertical displacement [delta] _F at the support point F, the limit time is not present.

  Next, among the calculated limit times, the limit time that arrives earliest is specified as the earliest limit time (FIG. 1, step 103).

In the above example, the limit time in the supporting point G and the supporting point E is present respectively, towards the limit time T _G in the estimation vertical displacement [delta] _G at the support point G is estimated vertical displacement [delta] _E at the support points E since arriving earlier than the limit time T _E at the limit time T _G at the support point G is longer the limit time T _C1.

Next, the displacement that should be adjusted at the start of excavation is defined as a provisional adjustment displacement so that the maximum value of each estimated vertical displacement up to the earliest limit time T _C1 is less than or equal to the upper limit of the control width and the minimum value is greater than or equal to the lower limit of the control width. Each is obtained (FIG. 1, step 104).

6 (a) is shows a calculation procedure of the provisional adjustment displacement of the support point G, the minimum in the support points, as before adjustment shown in FIG dashed line than the maximum value [delta] _max Since the value δ _min has a larger absolute value, the value δ _min falls below the lower limit of the management width without waiting for the earliest limit time T _C1 .

Therefore, the maximum value δ _max of the estimated vertical displacement δ _G up to the earliest limit time T _C1 at the support point G is Δ / 2, which is the upper limit of the management width Δ, and the minimum value δ _min is the lower limit of the management width Δ (− The adjustment displacement to be adjusted at the start of excavation is obtained as a provisional adjustment displacement so that Δ / 2). In the example of the figure, the temporary adjustment displacement is (Δ / 2−δ _max ).

At the support point G, the maximum value up to the earliest limit time T _C1 is set to be the upper limit of the management width Δ and the minimum value is set to the lower limit of the management width δ. There is no room, and the temporary adjustment displacement becomes the adjustment displacement as it is.

FIG 6 (b) is shows a calculation procedure of the provisional adjustment displacement at support point F and the supporting point E, for example, the support points E, as before adjustment shown in FIG dashed, the maximum value [delta] _max Since the minimum value δ _min is a negative value, it is far below the lower limit of the management width at the earliest limit time T _C1 .

Therefore, the provisional value to be adjusted at the start of excavation so that the median value of the maximum value δ _max and the minimum value δ _min of the estimated vertical displacement up to the earliest limit time T _C1 at the support point E becomes the median value of the management width. Find the adjustment displacement.

In the example of the figure, the provisional adjustment displacement at the support point E is an average value of the maximum value δ _max and the minimum value δ _min in the estimated vertical displacement δ _E up to the earliest limit time T _C1 .

  If the average value is positive, the estimated vertical displacement is adjusted in the negative direction. If the average value is negative, the estimated vertical displacement needs to be adjusted in the positive direction. Becomes negative.

  For the support point F, the temporary adjustment displacement may be obtained in the same manner as the support point E.

If the hydraulic jack 7 is operated so that the provisional adjustment displacements of the support points E, F, and G thus obtained are respectively applied to the support points at the start of excavation in the correction section, the correction section becomes an independent section. If this is the case, it is not necessary to correct the vertical displacement in the section until the earliest limit time T _C1 arrives, but in this embodiment, the underpinning work proceeds along the bridge axis direction of the viaduct 2. Therefore, it is necessary to consider the influence on other sections adjacent to the corrected section.

That is, the support point E calculated in accordance with the procedure described above, F, if each interim adjustment displacements of G, was added to the respective support points in time T ₁ is the start excavation modification section, the supporting points E, F, G The vertical displacement of the viaduct 2 at is changed as shown in FIGS. 7 (a) to 7 (b).

On the other hand, in the correction auxiliary section where excavation has been completed prior to the correction section, as shown in FIG. 8, the correction auxiliary section is the correction section at the support point C and the support point D located in the section. Sometimes, the provisional adjustment displacement calculated by the same procedure as the above-described steps 101 to 104 is added at time T ₂ when the excavation start of the correction auxiliary section is started.

Specifically, the earliest limit time T _C2 in the correction auxiliary section occurs at the support point D, and the maximum value up to the earliest limit time T _C2 at the support point coincides with the upper limit of the management width Δ, and the minimum value is A temporary adjustment displacement is applied so as to coincide with the lower limit of the management width δ, and at the support point C, the maximum value up to the earliest limit time T _C2 falls below the upper limit of the management width Δ, and the minimum value is the lower limit of the management width δ. If the supplementary adjustment displacement is added so that the correction auxiliary section is an independent section, the temporary adjustment displacements of the support points C and D are added to the support points at the start of excavation in the correction auxiliary section, respectively. By operating the hydraulic jack 7 as described above, it becomes unnecessary to correct the vertical displacement in the section until the earliest limit time T _C2 arrives.

  However, since the vertical displacement of the viaduct 2 needs to be smooth and continuous from the correction section to the non-correction section through the correction auxiliary section, the viaduct 2 after the provisional adjustment displacement is applied to the correction section As shown in FIG. 9 (b), the vertical displacement should be applied to the support point C and the support point D located in the correction auxiliary section so as to continue smoothly through the correction auxiliary section to the non-correction section. Temporary auxiliary adjustment displacement is obtained (FIG. 1, step 105). In addition, the broken line of FIG.9 (b) and FIG.9 (a) show the vertical displacement of the viaduct 2 before provisional adjustment displacement is added.

Here, if there is no influence from the correction section, the provisional auxiliary adjustment displacement described above is applied at the time T ₁ at the support points C and D where the adjustment operation should have been unnecessary until the earliest limit time T _C2 . The state of FIG. 8 (b) changes to the state of FIG. 9 (c). In the example of FIG. 9, the vertical displacement at the support point D has the management width Δ without waiting for the earliest limit time T _C2 to arrive. It falls below the lower limit.

In this case, the following three conditions (b-1), (b-2), and (b-3) described below, that is,
(b-1) Until the earliest limit time T _C2 related to the correction auxiliary section arrives, the maximum value of the estimated vertical displacement of the support points C and D in the section does not exceed the upper limit of the management width, and the minimum value is the lower limit of the management width Not less than
(b-2) Until the earliest limit time T _C1 related to the corrected section arrives, the maximum value of each estimated vertical displacement in the section does not exceed the upper limit of the management width, and the minimum value does not fall below the lower limit of the management width
(b-3) The above-described provisional auxiliary adjustment displacement is corrected to an auxiliary adjustment displacement so that the vertical displacement of the viaduct 2 in the correction section, the correction auxiliary section, and the non-correction section continues smoothly but is satisfied. The above-described provisional adjustment displacement is corrected to obtain an adjustment displacement (FIG. 1, step 106).

  In order to make the vertical displacement of the viaduct 2 continue smoothly, a known curve fitting method may be appropriately selected and employed.

FIG. 10 shows that at time T _{1 when} excavation is started in the correction section, adjustment displacement is applied to the support points E and F located in the correction section, and auxiliary adjustment is performed on the support points C and D located in the correction auxiliary section. This figure shows the vertical displacement of the viaduct 2 at the time when the displacement is applied and the fluctuation of the vertical displacement at each supporting point thereafter. In the correction auxiliary section, the earliest limit time T _C2 in the section arrives. The adjustment operation at the support point C and the support point D is unnecessary until the adjustment point, and in the correction section, the adjustment at the support point E and the support point F until the earliest limit time T _C1 in the section arrives. It can be seen that no operation is required.

As described above, at the support point G located in the correction section, the maximum value up to the earliest limit time T _C1 is set to be the upper limit of the management width Δ and the minimum value is set to the lower limit of the management width δ. Since there is no adjustment allowance, the provisional adjustment displacement becomes the adjustment displacement as it is.

Next, the support point C shown in FIG. 10, D, E, adjusting the displacement of the support point G shown in adjusting displacement and auxiliary shift displacement and FIGS. 6 (a) according to F is started drilling in the modified sections the time T ₁ , The vertical displacement of the viaduct 2 is adjusted by driving and controlling the hydraulic jacks 7 so as to be respectively added to the corresponding support points.

As described above, according to the displacement adjustment method in the underpinning according to the present embodiment and the jack control system 1 using the displacement adjustment method, after obtaining the adjustment displacement and the auxiliary adjustment displacement, respectively, when starting excavation in the correction section, By operating the hydraulic jack 7 so that the adjustment displacement occurs at the support points E, F, and G in the correction section, and the auxiliary adjustment displacement occurs at the support points C and D in the correction auxiliary section, the correction section and the correction auxiliary section Then, the vertical displacement of the viaduct 2 does not fall below the lower limit of the management width Δ or exceed the upper limit by the earliest limit times T _C1 and T _C2 in each section.

  Therefore, while ensuring smooth continuity of vertical displacement of the viaduct 2 over adjacent sections, the next adjustment of the vertical displacement that occurs in the viaduct 2 not only in the correction section to be excavated but also in the correction auxiliary section to be re-corrected The timing can be delayed as much as possible, and thus the frequency of adjusting the vertical displacement generated on the viaduct 2 during the construction period can be greatly reduced.

Further, according to the displacement adjusting method in the underpinning and the jack control system 1 using the same according to the present embodiment, the vertical displacement up to the earliest limit times T _C1 and T _C2 with respect to the other support points other than the support point G. The adjustment displacement and auxiliary adjustment displacement that should be adjusted at the start of excavation in the correction section are calculated so that the median value between the maximum value and the minimum value becomes the median value of the management width Δ. Then, the vertical displacement of the viaduct 2 can be kept within the management width Δ with a margin until the earliest limit time T _C1 or the earliest limit time T _C2 is reached.

In the present embodiment, by adding the provisional auxiliary adjustment displacement to the support points C and D, the support points C and D are reached until the earliest limit time T _C2 in the section when the correction auxiliary section is the correction section. In the above description, the maximum value of each estimated vertical displacement exceeds the upper limit of the management width Δ, or the minimum value is lower than the lower limit of the management width Δ. However, even if the provisional adjustment displacement is added to the support points C and D, the support point When the maximum value of each estimated vertical displacement in C and D does not exceed the upper limit of the management width Δ and the minimum value does not fall below the lower limit of the management width Δ, step 106 is omitted, and the above-described provisional adjustment displacement and provisional assistance are omitted. The adjustment displacement may be an adjustment displacement and an auxiliary adjustment displacement, respectively.

  In the present embodiment, the allowable width Δ is made to coincide with the management width of the vertical displacement at each support point. Instead, a reduction factor, for example, 0.9, 0.8, etc. is added to the management width. It can be multiplied by a number.

  With this configuration, it is possible to manage displacement with a margin.

  In the present embodiment, the estimated vertical displacement is corrected by setting the measurement result measured by the displacement meter 8 as an initial value. However, this may be omitted depending on circumstances.

  Further, in the present embodiment, at the start of excavation in the correction section, the adjustment displacement is generated at the support points E, F, G in the correction section, and the auxiliary adjustment displacement is generated at the support points C, D in the correction auxiliary section. Although a specific procedure for driving and controlling the hydraulic jack 7 is not particularly mentioned, it can be performed by the following procedure, for example.

That is, among the support points, each support point Rj (j = 1, 2,... When a unit amount of jack stroke is given to a certain support point Ri (i = 1, 2,... N).・ The vertical displacement that occurs in N) is calculated by the arithmetic processing unit 13 for each support point to obtain an influence coefficient fij (i = 1, 2,... N, j = 1, 2,... N). Then, the inverse matrix of the matrix [F] having the influence coefficient as an element is calculated as [F] ^{−1 by} the arithmetic processing unit 13 and the total adjustment displacement including the adjustment displacement and the auxiliary adjustment displacement described above is defined as {δ}. ,
{S} = [F] ⁻¹ {δ}
Is calculated so as to calculate the operation amount of each hydraulic jack 7 as a required stroke amount {s} (si (i = 1, 2,... N)), and the required stroke amount { Each hydraulic jack 7 can be configured to be driven and controlled by the control unit 9 based on s}.

This will be described in detail with respect to the case where there are nine support points supported by the hydraulic jack 7. The hydraulic jack installed at the support point R _j (j = 1, 2,... 9) of the viaduct 2 7, the stroke amount of the first hydraulic jack 7 is changed, that is, a stroke increment of s ′ ₁ is given to the hydraulic jack, and each support point R _i (i = 1, 2,... The vertical displacement δ ′ _i1 (i = 1, 2,... 9) of the viaduct 2 generated in 9) is measured by the displacement meter 8.

Next, the vertical displacement δ ′ _i1 (i = 1, 2,... 9) of the viaduct 2 measured at each support point R _i (i = 1, 2,... 9) is used as the first hydraulic jack. 7 is divided by the stroke amount s ′ ₁ and calculated by the arithmetic processing unit 13 as an influence coefficient f _i1 (i = 1, 2,... 9).

Next, by changing the stroke amount of the second hydraulic jack 7, the influence coefficient f _i2 (i = 1, 2,... 9) is calculated in the same procedure as described above. _The influence coefficients are calculated until _i9 (i = 1, 2,... 9).

Next, a matrix [F] whose elements are influence coefficients f _ij (i = 1, 2,..., J = 1, 2,... 9) obtained by the above-described procedure is shown in the following equation. As shown in FIG. That is,

Next, an inverse matrix [F] ⁻¹ of the matrix [F] is calculated by the arithmetic processing unit 13.

Next, the calculated inverse matrix [F] ⁻¹ is stored in the hard disk 10.

Next, let {δ} be the total adjustment displacement including the adjustment displacement and the auxiliary adjustment displacement described above,
{S} = [F] ⁻¹ {δ}

Is calculated so as to calculate the operation amount of each hydraulic jack 7 as a required stroke amount {s} (si (i = 1, 2,... N)), and the required stroke amount { s}, each hydraulic jack 7 is driven and controlled by the control unit 9.

  According to such a configuration, it is possible to reliably generate the adjustment displacement and the auxiliary adjustment displacement, respectively, and it is possible to significantly reduce the adjustment frequency of the vertical displacement generated on the viaduct 2 during the construction period. Can be effective.

1 Jack control system for underpinning 2 Viaduct (existing structure)
7 Hydraulic jack (jack)
9 Control unit (calculation control means)
13 Arithmetic processing part (arithmetic control means)

Claims (6)

When constructing an underground structure below the existing structure while transferring the load of the existing structure sequentially along the horizontal direction and for each section along the direction, the vertical displacement of the existing structure is adjusted. In the displacement adjustment method in underpinning,
Of the sections, the section to be excavated is the first section, the section adjacent to the first section and excavated in advance of the section is the second section, and the second section is the second section. A section that is adjacent on the opposite side of section 1 and that has been excavated prior to the first section and the second section is defined as a third section, and after the start of excavation in the first section The time history vertical displacement of the existing structure is calculated as an estimated vertical displacement at a plurality of support points provided in the existing structure to replace the load of the existing structure located in the section,
The time when the difference between the maximum value and the minimum value in each estimated vertical displacement first exceeds the allowable range is calculated as the limit time,
Among the limit times, the earliest limit time is specified as the earliest limit time,
The maximum value of each estimated vertical displacement up to the earliest limit time is less than the upper limit of the management width and the minimum value is greater than or equal to the lower limit of the management width.
The vertical displacement of the existing structure in the first section when each of the temporary adjustment displacements is applied to each of the support points smoothly continues with the vertical displacement of the existing structure in the third section. As described above, the displacement to be applied to the existing structure in the second section is obtained as a provisional auxiliary adjustment displacement,
The provisional auxiliary adjustment displacement is obtained by the series of steps when the second section is an object to be excavated when it is applied to the second section at the start of excavation of the first section. The maximum value of each estimated vertical displacement at the plurality of support points provided in the existing structure in the second section does not exceed the upper limit of the management width and is the minimum before the earliest limit time in the second section arrives When the value does not fall below the lower limit of the management width, the provisional adjustment displacement and the provisional auxiliary adjustment displacement are set as adjustment displacement and auxiliary adjustment displacement, respectively.
The provisional auxiliary adjustment displacement is applied to the second section at the start of excavation in the first section, and the second section has a maximum time until the earliest time limit for the second section arrives. When the maximum value of each estimated vertical displacement exceeds the upper limit of the management width or the minimum value is lower than the lower limit of the management width, each estimation in the second section until the earliest limit time for the second section arrives. Each estimated vertical in the first interval until the earliest limit time for the first interval arrives so that the maximum value of the vertical displacement does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width. The maximum value of displacement does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width, and the existing structures in the first section, the second section, and the third section The vertical displacement is continued smoothly. With the auxiliary shift displacement by modifying the constant auxiliary shift displacement, and adjusts the displacement and correct the provisional adjustment displacement,
The under displacement is characterized in that at the start of excavation in the first section, the adjustment displacement is applied to the support points in the first section, and the auxiliary adjustment displacement is applied to the support points in the second section. Displacement adjustment method in pinning. Among the adjustment displacements, the adjustment displacement that does not correspond to the earliest limit time in the first section or the auxiliary adjustment displacement is the median value of the maximum value and the minimum value of the estimated vertical displacement up to the earliest limit time. The displacement adjustment method in underpinning according to claim 1, wherein each is calculated so as to be a median value of the management width. Jacks respectively installed at a plurality of supporting points for each of the sections provided in the existing structure in order to receive the load of the existing structure sequentially in the horizontal direction and for each section along the direction; In the jack control system in underpinning, comprising arithmetic control means for operating each jack,
Among the sections, the arithmetic and control means is configured such that a section to be excavated is a first section, a section adjacent to the first section and excavated in advance of the section is a second section, the second section A section that is adjacent to the second section on the opposite side of the first section and that has been excavated prior to the first section and the second section is a third section, and the first section Estimated vertical displacement of the time history of the existing structure after excavation in the section at a plurality of support points located in the existing structure to receive the load of the existing structure located in the section The time when the difference between the maximum value and the minimum value in each estimated vertical displacement first exceeds the allowable range is calculated as the limit time, and the earliest limit time of the limit times is the earliest limit time. And each estimated lead up to the earliest limit time The displacement to be adjusted at the start of excavation is determined as a provisional adjustment displacement so that the maximum value of the displacement is less than or equal to the upper limit of the management width and the minimum value is greater than or equal to the lower limit of the management width. In the second section, the vertical displacement of the existing structure in the first section when added to the first section is smoothly continued with the vertical displacement of the existing structure in the third section. A displacement to be applied to an existing structure is obtained as a provisional auxiliary adjustment displacement, and the provisional auxiliary adjustment displacement is applied to the second section at the start of excavation in the first section, and the second section A plurality of supports provided in the existing structure in the second section until the earliest limit time in the second section is obtained by the series of steps when the object is an excavation target. When the maximum value of each estimated vertical displacement at the point does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width, the temporary adjustment displacement and the temporary auxiliary adjustment displacement are adjusted displacement and auxiliary adjustment displacement, respectively. The provisional auxiliary adjustment displacement is applied to the second section at the start of excavation of the first section, and the second limit time is reached before the earliest limit time for the second section arrives. In the case where the maximum value of each estimated vertical displacement in the section exceeds the upper limit of the management width or the minimum value is lower than the lower limit of the management width, in the second section until the earliest limit time for the second section arrives In order that the maximum value of each estimated vertical displacement does not exceed the upper limit of the management width and the minimum value does not fall below the lower limit of the management width, each of the first intervals until the earliest limit time of the first section arrives. The maximum estimated vertical displacement is The vertical displacement of the existing structure in the first section, the second section, and the third section is smooth so that the upper limit of the management width is not exceeded and the minimum value does not fall below the lower limit of the management width. The temporary auxiliary adjustment displacement is corrected to be an auxiliary adjustment displacement so as to be continuous, and the temporary adjustment displacement is corrected to be an adjustment displacement.
Among the jacks, the adjustment displacement is generated at the support point in the first section at the start of excavation in the first section, and the auxiliary adjustment displacement is generated at the support point in the second section. A jack control system in underpinning, characterized in that at least one of them is configured to be operable. The arithmetic and control means, among the adjustment displacement, the adjustment displacement or the auxiliary adjustment displacement not corresponding to the earliest limit time in the first section, the maximum value of the estimated vertical displacement up to the earliest limit time 4. The jack control system for underpinning according to claim 3, wherein a median value with a minimum value is determined to be a median value of the management width. The arithmetic control means is configured to provide the support points Rj (j = 1) when a jack stroke of a unit amount is given to a support point Ri (i = 1, 2,... N) among the support points. , 2,... N) is calculated for each of the support points, and the influence coefficient fij (i = 1, 2,... N, j = 1, 2,... N) is calculated. In addition, an inverse matrix of the matrix [F] having the influence coefficient as an element is calculated as [F] ⁻¹ , and an overall adjustment displacement including the adjustment displacement and the auxiliary adjustment displacement is {δ},
{S} = [F] ⁻¹ {δ}
The operation amount of each jack is calculated as a required stroke amount {s} (si (i = 1, 2,... N)) by calculating Jack control system for underpinning as described. The jack control system for underpinning according to any one of claims 3 to 5, further comprising vertical displacement measuring means for measuring the vertical displacement of the existing structure at each of the support points.

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