CN108729461A - For the constructing structure and construction method on aerial leakage stratum in deep hole impervious wall construction - Google Patents

Abstract

The invention relates to a construction structure and a construction method for overhead leakage strata in the construction of deep hole anti-seepage walls, and belongs to the construction technology of concrete anti-seepage walls in water conservancy and hydropower projects. It includes the anti-seepage wall and the guide grooves on both sides of the axis of the anti-seepage wall. The key technology is to arrange steel pipe pile holes on the central axis of the guide groove, and to install grouted steel pipes in the steel pipe pile holes, and pour mortar into the grouted steel pipes to form Steel pipe piles. The construction method includes stratum judgment, drilling, grouting steel pipes and steel pipe pile grouting. The present invention is aimed at different formations, the steel pipe piles are arranged in different densities and depths, and the steel pipes play the role of locking boulders and sandy soil, fully filling and consolidating weak links in the formation, preventing, reducing or even avoiding seepage prevention Accidents such as slot collapse, slurry leakage, and piping occurred during the wall construction, so as to achieve the purpose of solid wall protection for the cut-off wall construction, improve the work efficiency of the cut-off wall, and provide a reliable guarantee for the construction quality and stability of the cut-off wall .

Description

Construction structure and construction method for overhead leakage stratum in construction of deep hole anti-seepage wall

technical field

The invention relates to a construction structure and a construction method for overhead leakage strata in the construction of deep hole anti-seepage walls, and belongs to the construction technology of concrete anti-seepage walls in water conservancy and hydropower projects.

Background technique

In water conservancy and hydropower projects, concrete cut-off walls, as a commonly used foundation anti-seepage treatment method, have been widely used in the anti-seepage treatment of foundation pits of hydropower station projects, but in the construction of cut-off walls, cofferdams are often encountered underwater fill Complex formations such as dense backfill layers and overhead leakage formations cannot be rolled and compacted by construction. Accidents such as slurry leakage, hole collapse, and piping are very likely to occur in the construction of cutoff walls in such strata, especially in the construction of cutoff walls with deep holes of 50m and above, the hazards of such strata are particularly great. Once an accident occurs, it will not only directly have a great impact on the safety of the construction personnel's equipment and the groove section, but also the accident handling will indefinitely prolong the groove formation cycle of the cutoff wall, seriously affecting the normal progress of the construction and increasing the cost investment.

The "backfilling method" is generally used to deal with accidents in the construction of cutoff walls. The commonly used "backfilling method" is more practical, but the construction efficiency is extremely low; The lower part of the wall, while the traditional "backfilling method" for the collapse of the slot and the loss of the formation area is to backfill the clay and add stones, and use the impact drill to repeatedly impact and squeeze the wall of the slot to make the wall dense. It is necessary to backfill all the part of the formed groove to the guide wall and repeat the construction several times to ensure compaction, which is extremely unfavorable to the construction of cut-off walls in deep holes (above 50m level), and the disturbance is relatively large during the impact process of hole making , The slot hole is also very easy to collapse again and leak slurry.

Contents of the invention

The problem to be solved by the present invention is to provide a structure that can safely and quickly carry out cut-off wall construction for complex strata such as deep hole (above 50m level) cofferdam underwater filling that cannot be rolled and compacted, dense backfill layer, overhead leakage stratum, etc. and construction methods. Its technical scheme is as follows:

It includes the anti-seepage wall and the guide grooves on both sides of the axis of the anti-seepage wall. The key technology is to arrange steel pipe pile holes on the central axis of the guide groove, and to install grouted steel pipes in the steel pipe pile holes, and pour mortar into the grouted steel pipes to form Steel pipe piles.

The distance between the steel pipe pile holes is 1.5m-2m.

Process quincunx-shaped holes at intervals of 30cm to 35cm on the wall of the grouted steel pipe.

When the length of the grouting steel pipe is increased, the threaded connection is adopted.

Its construction method includes the following steps:

1) stratum judgment;

2) Drilling preparation: After the excavation of the guide groove of the cut-off wall is completed, before the pouring of the guide groove, the steel pipe pile holes are arranged along the central axis of the guide groove of the cut-off wall according to the designed spacing, and the drilling rig is prepared and in place;

3) Drilling: After the drilling rig is in place, first align the center of the eccentric drill bit with the reaming sleeve with the steel pipe pile hole marked and positioned to ensure the verticality of the drilling hole, and then drill with the pipe to the designed hole depth;

4) Set up grouted steel pipes: after the boreholes pass the inspection and acceptance, install grouted steel pipes into the steel pipe pile holes, and the upper opening of the grouted steel pipes exceeds the height of the bottom of the guide groove 1 by 50-60 cm;

5) Steel pipe pile grouting: No need to pressurize during grouting construction, just use the grouting pump to transport the grout to the hole of the grouted steel pipe, and use the mortar to inject the hole into the hole by its own weight. After the grout fills the steel pipe pile hole, the hole The grout level no longer drops, stop grouting, and form steel pipe piles.

Compared with prior art, the beneficial effect that the present invention has is:

1. Compared with the cofferdam backfill layer and leakage overhead layer treatment process carried out during the trench formation process of the conventional anti-seepage wall, the present invention adopts advanced pre-filled mortar steel pipe piles to reinforce the construction structure, and pours mortar through the steel pipe piles. For different strata, steel pipe piles are arranged in different densities and depths. The steel pipes play the role of locking boulders and sand, and can fully fill and consolidate weak links in the stratum, improve the integrity of the stratum, prevent, reduce or even Avoid accidents such as slot collapse, slurry leakage, and piping in the construction of the cutoff wall, so as to achieve the purpose of solid wall protection in the construction of the cutoff wall, improve the work efficiency of the cutoff wall, and provide a guarantee for the construction quality and stability of the cutoff wall a reliable guarantee.

2. This structure prevents, reduces or even avoids the occurrence of accidents such as slot collapse, slurry leakage, and piping during the construction of the cut-off wall, so it reduces the waste of resources caused by handling accidents and saves construction costs.

3. The adoption of this structure makes the construction fast, safe and reliable, speeds up the construction progress and reduces the construction cost.

4. The structure is suitable for the construction of deep hole anti-seepage walls above 50m level.

Description of drawings

Fig. 1 is a schematic diagram of the plane structure of the present invention;

Fig. 2 is a schematic cross-sectional structure diagram of Fig. 1A-A.

Detailed ways

The present invention will be further described below in conjunction with specific embodiment, and specific embodiment is a further description of the principle of the present invention, does not limit the present invention in any way, and the same or similar technologies as the present invention do not exceed the protection scope of the present invention.

Referring to Fig. 1 and Fig. 2, the present invention includes the anti-seepage wall and guide grooves 1 on both sides of the anti-seepage wall axis 4, and its key technology is to arrange steel pipe pile holes 3 on the central axis 2 of the guide groove, and inside the steel pipe pile holes 3 A grouting steel pipe 5 is arranged below, and mortar is poured into the grouting steel pipe 5 to form a steel pipe pile.

The distance between the steel pipe pile holes 3 is 1.5m-2m.

The grouting steel pipe 5 is made of a Φ89mm steel pipe.

Oxygen welding is used to process plum blossom-shaped holes 6 with a diameter of 2 cm on the wall of the grouting steel pipe at intervals of 30 cm to 35 cm, so as to improve the grouting effect and increase the radiation range of the grout.

The length of the grouting steel pipe 5 is set according to the depth of the construction hole, and generally the length of a single steel pipe is 6m-8m.

The upper and lower grouting steel pipes 5 are connected with screws to increase the length.

When the length of the grouted steel pipe 5 is increased, two connecting reinforcing bars are provided outside the threaded connection to prevent the pipe fittings from falling off during the lowering process.

The upper opening of the grouted steel pipe 5 exceeds the height of the bottom of the guide groove 1 by 50-60 cm, and is poured in the guide groove 1 after the grouting in the later stage to increase the stability of the steel pipe pile.

The construction method for overhead leakage stratum in the construction of deep hole cutoff wall includes the following steps:

1) Stratum judgment: In the early stage, according to the nature of the cofferdam filling at the construction site and the design and exploration data, the properties of the construction stratum are determined, the construction area that needs to be pre-treated is determined, and the pile spacing and hole depth are determined according to the specific geological conditions;

2) Drilling preparation: After the excavation of the guide groove of the cut-off wall is completed, before the pouring of the guide groove, the steel pipe pile holes 3 are arranged along the central axis 2 of the guide groove of the cut-off wall according to the design interval of 1.5m ~ 2m, and the drilling center is made of lime. Mark positioning, drilling rig preparation and positioning;

3) Drilling equipment: In order to improve the construction efficiency, Atlas A66CBT full-hydraulic crawler drilling rig and Ingersoll Rand XHP900WCAT air compressor are selected for drilling construction;

4) Aperture diameter: Use Φ127mm eccentric drill bit with Φ140mm casing to drill into the hole;

5) Drilling by eccentric drilling process: After the drilling rig is in place, first align the center of the φ127mm eccentric drill bit with a reaming sleeve with the marked steel pipe pile hole 3, and check with a level ruler to ensure the verticality of the drilling. Then drill with the pipe, use the "hammer type" inclinometer to detect the hole inclination during drilling, and correct the deviation immediately if the drilling deviation is found, and drill in this way to the design hole depth;

6) Underlying grouted steel pipes: After the boreholes are qualified, according to the depth, the verticality of the upper and lower two grouted steel pipes 5 is corrected. A grouted steel pipe 5 is set in the hole 3; the upper opening of the grouted steel pipe exceeds the height of the bottom of the guide groove 1 by 50-60 cm, and the grouted steel pipe is poured in the guide groove 1 after the grouting is completed in the later stage to increase the stability of the steel pipe pile;

The grouting steel pipe 5 is made of a Φ89mm steel pipe, and the length of a single pipe is generally 6m.

Oxygen welding is used to process quincunx-shaped holes 6 with a diameter of 2 cm at intervals of 30 cm to 35 cm on the grouted steel pipe wall.

In order to reach the length of the grouting steel pipe 5, the 5 head and tail ends of the grouting steel pipe can be connected with screws to increase its length.

In order to prevent the pipe fittings from falling off during the lowering process, 2 connecting reinforcing steel bars are arranged on the outside of the threaded joint that increases the length of the grouted steel pipe 5 for fastening.

7) Steel pipe pile grouting: One J-400 high-speed pulping machine is used to mix high-fluid mortar. The sand used for grouting is hard natural or machine-made medium-fine sand, with a particle size of not more than 2.5mm and a fineness of The modulus is not more than 2.0, the mud content is not more than 3%, the SO3 content is less than 1%, and the organic matter content is not more than 3%; the grouting equipment uses TTB100/20 medium pressure variable grouting pump to transport cement mortar, no need for grouting construction Pressurization, just use the grouting pump to transport the grout to the hole of the grouting steel pipe, and inject the grout into the hole by its own weight to avoid excessive pressure and cause the grout to spread too much, causing unnecessary waste of resources. When the steel pipe pile hole is full, the grout level of the hole will no longer drop, and the grouting will be stopped to form a steel pipe pile.

The drilling method of the eccentric follow-through drilling method is the impact rotary form, and the drilling tool of the eccentric drilling process is composed of three sets of drilling tools (rod stabilizer, center drill bit, and eccentric drill bit). The drilling process is to rely on the center drill bit to drill into the bottom rock, the eccentric drill bit breaks the rock around the hole wall to ream the hole, and the rod stabilizer drives the outer wall casing to follow up to form a hole; after drilling to the design depth, reverse rotation Drill pipe, retract the eccentric drill bit, extract the drill pipe and drill tool to form a hole.

Claims (9)

1. for the constructing structure on aerial leakage stratum, including cut-pff wall and cut-pff wall axis in a kind of deep hole impervious wall construction (4) guide groove (1) of both sides, it is characterized in that steel pipe stake holes (3) is arranged on guide groove central axis (2), in steel pipe stake holes (3) Slip casting steel pipe (5) is divided into, the interior perfusion mortar of slip casting steel pipe (5) forms steel-pipe pile.

2. according to claim 1 for the constructing structure on aerial leakage stratum in deep hole impervious wall construction, it is characterized in that steel The spacing of hole of post (3) is 1.5m~2m.

3. according to claim 1 for the constructing structure on aerial leakage stratum in deep hole impervious wall construction, it is characterized in that note Slurry steel pipe (5) is made of the steel pipe of Φ 89mm.

4. according to claim 1 for the constructing structure on aerial leakage stratum in deep hole impervious wall construction, it is characterized in that At interval of 30cm~35cm processing plum blossom-shaped holes (6) in slip casting steel pipe walls.

5. according to claim 1 for the constructing structure on aerial leakage stratum in deep hole impervious wall construction, it is characterized in that note The joint length for starching steel pipe (5) is 6~8m.

6. according to claim 1 for the constructing structure on aerial leakage stratum in deep hole impervious wall construction, it is characterized in that note It starches steel pipe (5) and uses screwed connection.

7. according to claim 6 for the constructing structure on aerial leakage stratum in deep hole impervious wall construction, it is characterized in that note It starches outside at steel pipe (5) screwed connection and connection reinforcement reinforcing bar is set.

8. according to claim 1 for the constructing structure on aerial leakage stratum in deep hole impervious wall construction, it is characterized in that note Starch steel pipe (5) height suitable for reading beyond 1 50~60cm of bottom of guide groove.

9. for the construction method on aerial leakage stratum in deep hole impervious wall construction described in claim 1, it is characterised in that including Following steps：

1) stratum judges；

2) drilling prepares：Before waiting for that guide groove pours after the completion of cut-pff wall guide groove excavates, along cut-pff wall guide groove central axis (2) According to design spacing arrangement steel pipe stake holes (3), drilling machine prepares and in place；

3) it drills：After drilling machine is in place, off-balance bit center will be covered with reaming first and the steel pipe stake holes (3) of label positioning carries out pair Just, it is ensured that then borehole perpendicularity carries out pipe-following drilling to designing hole depth；

4) slip casting steel pipe is divided into：It drills after acceptance(check), divides into slip casting steel pipe (5) into steel pipe stake holes (3), slip casting steel pipe is suitable for reading Height beyond guide groove (1) 50~60cm of bottom；

5) steel-pipe pile is in the milk：Without pressurization when mortar depositing construction, only slurries need to be delivered to slip casting steel pipe aperture i.e. using grouting pump Can, using in mortar dead weight injection hole, wait for that slurries fill steel pipe stake holes, aperture pulp surface no longer declines, and stops slip casting, forms steel pipe Stake.