High earth-rock dam monitoring strip construction method and construction auxiliary device for the method

Abstract

A high earth-rock dam monitoring strip construction method, comprising the following steps: 1) strip ditch is excavated along the excavation line; 2) after the excavation and rolling are flattened, the transition material is backfilled on the ditch bottom; 3) the left half of the ditch bottom is backfilled, and the concrete base, the water pipe type settlement instrument and the tensioned line horizontal displacement meter are installed; 4) the right half of the ditch bottom is backfilled and the water pipe type settlement instrument pipeline is installed; 5) the instrument periphery is backfilled; 6) the pipeline periphery is backfilled. The method can solve the problems of low strip construction efficiency and low construction precision caused by manual excavation in the prior art, ensure the foundation stability of the monitoring equipment, and greatly reduce the interference of the excavation operation on the original compacted filler with the auxiliary device.

Description

Technical Field

[0001] This invention relates to the field of high earth-rock dam construction technology, specifically a method for constructing monitoring strips for high earth-rock dams. Background Technology

[0002] In the field of earth-rock dam safety monitoring, water-tube settlement gauges and tension line displacement gauges are generally used to monitor the internal settlement and horizontal displacement of the dam body. The "Technical Specification for Safety Monitoring of Earth-Rock Dams" (DL / T 5259, SL551) also clearly states that "when internal deformation monitoring adopts a horizontal layered arrangement, water-tube settlement gauges and tension line displacement gauges should be used." Water-tube settlement gauges and tension line displacement gauges are generally buried within the monitoring strip. Because of their simple structure, convenient observation, ability to adapt to large deformations in earth-rock dams, and automated monitoring capabilities, they are widely used in earth-rock dams.

[0003] Depending on the construction method, monitoring strip construction can be divided into trench method, ditch method, and trench-ditch hybrid method.

[0004] Among the existing construction methods mentioned above, the trench method is mainly used for strip construction because it is easy to protect pipelines, the pipeline slope can be strictly controlled, the backfill material is easy to compact, it can be mechanized, and it is highly efficient.

[0005] In the trench method, the trenches for water-tube settling meters generally employ three methods: uniform slope, partial slope, and segmented slope. The trenches for tension wire displacement gauges are typically horizontally arranged or have the same slope as the water-tube settling meters. Since water-tube settling meters and tension wire horizontal displacement gauges are usually arranged together in high earth-rock dams, and the installation of tension wire horizontal displacement gauges generally requires a smooth subgrade bed, using partial or segmented slope methods would make installation difficult. Therefore, the uniform slope method is now generally used for strip pipelines in high earth-rock dams.

[0006] In the uniform slope method, taking horizontal excavation as an example, the trench for the water-tube settlement meter is manually excavated next to the horizontal displacement pipeline. Because the strip subgrade compaction adopts the dam filling compaction standard, the compaction density is high, resulting in low efficiency for manual pipeline excavation. Furthermore, the strip pipeline of high earth-rock dams is generally designed with a slope greater than 1%, and the maximum length of the strip in high earth-rock dams generally exceeds 400m. This means that the height difference from the first measuring point to the downstream observation house exceeds 4m, which is beyond the height of the strip subgrade excavation and backfill material. Therefore, implementing this method by manually excavating trenches is extremely difficult and inefficient (generally 15-30 days).

[0007] Taking a slope gradient of 1.3% as an example, since the water-tube settling meter's pipeline is made of nylon plastic, to enhance the protection of the tension wire and the water-tube settling meter pipeline, trenches are typically excavated manually after the strip subgrade has been mechanically compacted. The pipelines are then installed in the trenches, and fine material is backfilled afterwards. This maximizes the location of the instrument pipeline within the core protection area of ​​the strip, enhancing the survival rate of the instrument pipeline. However, since the trenches are excavated manually, the original compacted fill material will be disturbed, which will have a certain impact on the determination of the monitoring instrument's benchmark value and subsequent observations. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a construction method for monitoring strips of high earth-rock dams. The mechanical excavation method effectively improves construction efficiency and reduces interference with the civil construction of the dam body. At the same time, it does not disturb the original compacted filling material. The method has virtually no impact on the determination of the benchmark value of the monitoring instrument and subsequent observation.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for constructing monitoring strips for high earth-rock dams, characterized by comprising the following steps:

[0010] 1) Strip foundation excavation

[0011] After the dam body filling elevation exceeds the instrument burial elevation by at least 1.2m, the strip trench is excavated along the excavation face.

[0012] 2) Strip subgrade backfilling;

[0013] After excavation and compaction, a transition material is backfilled at the bottom of the trench and compacted with a mechanical vibratory roller. Then, a layer of filter material is backfilled and compacted with a mechanical vibratory roller. Finally, a layer of filter material is backfilled on the left half of the trench bottom strip bed and compacted with a mechanical vibratory roller.

[0014] 3) Instrument installation

[0015] After the strip foundation excavation and acceptance are completed, before installing the water pipe type settlement meter, a precast concrete base is first installed in the left half of the strip foundation at the bottom of the trench. Then, the water pipe type settlement meter and tension wire horizontal displacement meter are installed on the strip foundation that has been excavated, backfilled and compacted.

[0016] 4) Trench backfilling

[0017] The right half of the water pipe sedimentation meter pipeline at the bottom of the ditch was backfilled with fine material with a particle size of less than 5mm to the installation elevation of the measuring point, and then manually compacted evenly.

[0018] 5) Backfilling around the instrument

[0019] During the filling process, first backfill the filter material on the foundation surface of the measuring point, backfilling to 20cm above the upper surface of the instrument measuring head, and compact it with a plate rammer or hand rammer. Then backfill a layer of transition material, compact it with a plate rammer or hand-held small roller, and finally backfill a layer of dam filling material, compacting it with a static roller.

[0020] 6) Backfilling around the pipeline

[0021] Backfill a layer of filter material on top of the already compacted filter material, and compact it with a plate rammer or a hand-held small roller. Then backfill a layer of transition material and compact it with a static roller. Finally, backfill a layer of dam fill material and compact it with a static roller.

[0022] In the preferred embodiment, in step 1), the excavated strip ditch is excavated from the first measuring point upstream of the dam to the observation house.

[0023] In the preferred embodiment, the strip ditch at the first measuring point upstream of the dam body is 2m deep, and the bottom of the ditch extends downstream to the observation house with a slope of 1.3%.

[0024] In the preferred embodiment, step 2) is carried out on the rockfill area;

[0025] When constructing on the filter layer and transition layer, the original fill material is backfilled at the bottom of the trench and compacted with a mechanical vibratory roller. Then, the original fill material with a particle size greater than 2cm is backfilled and compacted with a mechanical vibratory roller. Finally, a 20cm thick layer of the original fill material with a particle size greater than 2cm is backfilled on the left half of the bottom of the trench and compacted with a mechanical vibratory roller.

[0026] In the preferred embodiment, step 5) involves backfilling the rockfill area;

[0027] When backfilling on the filter layer and transition layer, first backfill the original fill material with a particle size greater than 2cm on the foundation surface of the measuring point, and backfill to a height of 20cm above the upper surface of the instrument measuring head. Then compact it with a plate rammer or hand rammer. Next, backfill a thick layer of the original fill material and compact it with a plate rammer or hand-held small roller. Finally, backfill a layer of the original fill material and compact it with a static roller.

[0028] In the preferred embodiment, step 6) involves backfilling the rockfill area;

[0029] When backfilling on the filter layer and transition layer, a layer of original fill material with particle size greater than 2cm is backfilled on top of the already compacted original fill material. The original fill material is compacted by using a plate rammer or a hand-held small roller. Then, two layers of original fill material are backfilled and compacted by static rolling.

[0030] The strip construction auxiliary device used for the above-mentioned high earth-rock dam monitoring strip construction method includes a trench plate, the bottom of which is provided with a trench plate with the same size as the excavation surface, and vertical plates are provided on the upper ends of both sides of the trench plate, and guide protrusions are provided on the outer wall of the vertical plates.

[0031] The auxiliary device also includes a ditch edge fixing plate, which is fixed to both sides of the ditch. The side wall of the ditch edge fixing plate facing the ditch is provided with a guide groove with an inclination angle the same as the slope of the ditch.

[0032] In a preferred embodiment, the grooved plate has two guide protrusions on one side, and the angle between the line connecting the two guide protrusions and the horizontal line is the same as the inclination angle of the guide groove.

[0033] The present invention provides a method for constructing monitoring strips for high earth-rock dams, which has the following beneficial effects:

[0034] (1) The entire process of trench excavation and backfilling in this construction plan is carried out by mechanical construction. The excavation of the 100m long strip and the installation of instruments can be completed in just 2 days, which greatly improves the work efficiency and has little interference with the civil construction of the dam. At the same time, since the original compacted fill material is not disturbed, this method has little impact on the determination of the benchmark value of the monitoring instrument and subsequent observation.

[0035] (2) The installation scheme of “keeping all measuring points at the same elevation” was cancelled, and a prefabricated 60cm×20cm×20cm concrete base was adopted. On the one hand, it greatly saved the time of on-site pouring of mortar and masonry, and on the other hand, it ensured the stability of the water pipe type settlement meter foundation, which greatly improved the work efficiency.

[0036] (3) The key points and critical contradictions of the monitoring strip construction were grasped. The trench excavation and backfilling were achieved by mechanical equipment, which not only achieved fine protection of the instrument pipeline, but also avoided manual trench excavation and reduced the amount of excavation work. At the same time, the whole process can be mechanized and the slope of the excavated trench can be precisely controlled, thus achieving fine construction.

[0037] (4) Using trench-shaped plates as protection during the excavation process can avoid disturbing the original compacted filling material by the excavation equipment while ensuring construction accuracy, thus ensuring the overall stability of the dam body. Attached Figure Description

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0039] Figure 1 This is a schematic diagram of the structure when using the trench method for strip excavation in the background art of this invention.

[0040] Figure 2This is a schematic diagram of the structure when using the trench method for strip excavation in the background art of this invention.

[0041] Figure 3 This is a schematic diagram of the strip construction auxiliary device in this invention.

[0042] Figure 4 This is a schematic diagram of the grooved plate structure of the present invention.

[0043] Figure 5 This is a schematic diagram of the groove edge fixing plate structure of the present invention.

[0044] In the diagram: 1. Excavation face; 2. Transition material; 3. Filter material; 4. Fine material; 5. Concrete base; 6. Water pipe type settlement meter; 7. Tension line horizontal displacement meter; 8. Water pipe type settlement meter pipeline; 9. Dam body fill material; 10. Trench profile plate; 11. Trench side fixing plate; 12. Guide protrusion; 13. Guide inclined groove. Detailed Implementation

[0045] Example 1:

[0046] like Figure 1-3 A method for constructing monitoring strips for high earth-rock dams, characterized by the following steps:

[0047] 1) Strip foundation excavation

[0048] After the dam body filling elevation exceeds the instrument burial elevation by at least 1.2m, excavate the strip trench along the excavation face 1.

[0049] 2) Strip subgrade backfilling;

[0050] After excavation and compaction, a transition material 2 is backfilled at the bottom of the trench and compacted with a mechanical vibratory roller. Then, a layer of filter material 3 is backfilled and compacted with a mechanical vibratory roller. Finally, a layer of filter material (3) is backfilled on the left half of the trench bottom strip bed and compacted with a mechanical vibratory roller.

[0051] 3) Instrument installation

[0052] After the strip foundation bed excavation and acceptance are completed, before the water pipe type settlement meter 6 is installed, a precast concrete base 5 is installed in the left half of the strip foundation bed at the bottom of the ditch. Then, the water pipe type settlement meter (6) and the tension line horizontal displacement meter 7 are installed on the strip foundation bed that has been excavated, backfilled and compacted.

[0053] 4) Trench backfilling

[0054] The right half of the water pipe sedimentation meter pipeline at the bottom of the ditch was backfilled with fine material with a particle size of less than 5mm to the installation elevation of the measuring point, and then manually compacted evenly.

[0055] 5) Backfilling around the instrument

[0056] During the filling process, first backfill the filter material 3 on the foundation surface of the measuring point, backfill to 20cm above the upper surface of the instrument measuring head, and compact it with a plate rammer or hand rammer. Then backfill a layer of transition material 2, compact it with a plate rammer or hand-held small roller, and finally backfill a layer of dam filling material, compact it with a static roller.

[0057] 6) Backfilling around the pipeline

[0058] Backfill a layer of filter material 3 on top of the already compacted filter material 3, and compact it with a plate rammer or a hand-held small roller. Then backfill a layer of transition material 2 and compact it with static rolling. Finally, backfill a layer of dam fill material and compact it with static rolling.

[0059] In the preferred embodiment, in step 1), the excavated strip ditch is excavated from the first measuring point upstream of the dam to the observation house.

[0060] In the preferred embodiment, the strip ditch at the first measuring point upstream of the dam body is 2m deep, and the bottom of the ditch extends downstream to the observation house with a slope of 1.3%.

[0061] In the preferred embodiment, step 2) is carried out on the rockfill area;

[0062] When constructing on the filter layer and transition layer, the original fill material is backfilled at the bottom of the trench and compacted with a mechanical vibratory roller. Then, the original fill material with a particle size greater than 2cm is backfilled and compacted with a mechanical vibratory roller. Finally, a 20cm thick layer of the original fill material with a particle size greater than 2cm is backfilled on the left half of the bottom of the trench and compacted with a mechanical vibratory roller.

[0063] In the preferred embodiment, step 5) involves backfilling the rockfill area;

[0064] When backfilling on the filter layer and transition layer, first backfill the original fill material with a particle size greater than 2cm on the foundation surface of the measuring point, and backfill to a height of 20cm above the upper surface of the instrument measuring head. Then compact it with a plate rammer or hand rammer. Next, backfill a thick layer of the original fill material and compact it with a plate rammer or hand-held small roller. Finally, backfill a layer of the original fill material and compact it with a static roller.

[0065] In the preferred embodiment, step 6) involves backfilling the rockfill area;

[0066] When backfilling on the filter layer and transition layer, a layer of original fill material with particle size greater than 2cm is backfilled on top of the already compacted original fill material. The original fill material is compacted by using a plate rammer or a hand-held small roller. Then, two layers of original fill material are backfilled and compacted by static rolling.

[0067] Example 2:

[0068] Based on the high earth-rock dam monitoring strip construction method described in Example 1, a strip construction auxiliary device is used for strip excavation construction. The strip construction auxiliary device includes a trench plate 10. The bottom of the trench plate 10 is provided with a trench plate with the same size as the excavation surface (1). Vertical plates are provided on the upper ends of both sides of the trench plate. Guide protrusions 12 are provided on the outer wall of the vertical plate.

[0069] The auxiliary device also includes a ditch edge fixing plate 11, which is fixed on both sides of the ditch. The ditch edge fixing plate 11 has a guide groove 13 with the same inclination angle as the slope of the ditch on the side wall facing the ditch.

[0070] In a preferred embodiment, the grooved plate 10 has two guide protrusions 12 on one side, and the angle between the line connecting the two guide protrusions 12 and the horizontal line is the same as the inclination angle of the guide groove 13.

[0071] Example 3:

[0072] Based on Example 2, when using a strip construction auxiliary device for trenching excavation:

[0073] 1) Use an excavator to excavate a trench of no more than 2m in length at the construction site, and place the trench template 10 at the downstream end of the trench to ensure that the bottom of the trench template 10 fits the trench.

[0074] 2) Use a propulsion device (jack or hydraulic support) to push the trench plate 10 downstream until the trench plate 10 is pressed into the dam body in the downstream construction area;

[0075] 3) Excavation work is carried out above the trench slab 10 to expose the trench slab 10;

[0076] 4) Install monitoring instruments in the excavated trench and backfill according to the method described in Example 1;

[0077] 5) Repeat steps 2)-4), using segmented excavation and backfilling to complete the excavation, equipment installation and backfilling of the entire strip.

[0078] In the above method, multiple ditch edge fixing plates 11 are configured, and the lowest end of the guide groove 13 on the multiple ditch edge fixing plates 11 gradually changes in height with the bottom of the ditch edge fixing plate 11, so as to achieve splicing during construction.

Claims

1. An auxiliary device for monitoring strip construction of high earth-rock dams, characterized in that: It includes a trench plate (10), the bottom of the trench plate (10) is provided with a groove plate with the same size as the excavation surface (1), the upper ends of both sides of the groove plate are provided with vertical plates, and the outer wall of the vertical plates is provided with guide protrusions (12). The auxiliary device also includes a ditch side fixing plate (11), which is fixed on both sides of the ditch. The ditch side fixing plate (11) has a guide chute (13) with the same inclination angle as the slope of the ditch on one side wall facing the ditch. The grooved plate (10) is provided with two guide protrusions (12) on one side. The angle between the line connecting the two guide protrusions (12) and the horizontal line is the same as the inclination angle of the guide groove (13). Multiple ditch edge fixing plates (11) are configured, and the lowest end of the guide groove (13) on the multiple ditch edge fixing plates (11) gradually changes in height with the bottom of the ditch edge fixing plate (11), so that they can be spliced ​​during construction. The method for trench excavation using the aforementioned auxiliary device includes the following steps: 1) Use an excavator to excavate a trench of no more than 2m in length at the construction site in advance, and place the trench plate (10) at the downstream end of the trench to ensure that the bottom of the trench plate (10) fits the trench. 2) The trench plate (10) is pushed downstream by a propulsion device until the trench plate (10) is pressed into the dam body in the downstream construction area; 3) Excavation work is carried out above the trench slab (10) to expose the trench slab (10); 4) Install monitoring instruments in the excavated trench and backfill; 5) Repeat steps 2)-4), using segmented excavation and backfilling to complete the excavation, equipment installation and backfilling of the entire strip.

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