Temporary newly-added downcast tube well system suitable for deep foundation pit construction

Abstract

The utility model relates to the technical field of deep foundation pit construction, in particular to a temporary measure of a deep foundation pit, and particularly relates to a downcast pipe well system which is temporarily added in the deep foundation pit construction. Comprising a steel platform, a steel casing and a casing support, the steel platform is arranged on the ground, the casing support is longitudinally arranged along each layer of latticed columns of the deep foundation pit, and the steel casing is arranged in the casing support in a penetrating mode. According to the downcast tube well system, the steel platform is arranged on the formed latticed column or the upper layer supporting structure, then the steel platform serves as a supporting face to insert the steel mutual pipe into the excavation face of the foundation pit, the steel mutual pipe is inserted into the foundation pit, hole cleaning operation is conducted on the bottom of the steel mutual pipe subsequently, finally, a drainage pipe is inserted into the steel mutual pipe, and water pumping equipment is arranged. Therefore, a complete temporary dewatering system which does not conflict with the working face of the foundation pit is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of deep foundation pit construction, in particular to temporary measures for deep foundation pits, in particular to a temporary new drainage pipe well system suitable for deep foundation pit construction. Background Art

[0002] Due to the large depth of the foundation pit, large depth of dewatering, large amount of water gushing from the foundation pit, etc., deep foundation pit dewatering operations usually require the selection and arrangement of reasonable well point dewatering, i.e., tube well dewatering methods, in advance to ensure that the groundwater level reaches the dewatering requirements, provided that there are no other important buildings around.

[0003] However, in actual construction, it is still encountered that the pressure water level is difficult to lower during the excavation process, and additional drainage pipes and wells are needed. At this time, the temporary addition of drainage pipes and wells is an unplanned matter. Therefore, it is possible to interfere with other ongoing construction projects on the foundation pit excavation surface, thereby posing a major safety problem. Utility Model Content

[0004] The utility model aims to overcome the above-mentioned defects and proposes a drainage pipe well system suitable for temporarily adding in deep foundation pit construction.

[0005] In order to achieve the above object, the utility model is achieved as follows:

[0006] A dewatering pipe well system suitable for temporary addition during deep foundation pit construction comprises a steel platform, a steel casing and a casing support, wherein the steel platform is arranged on the ground, the casing support is longitudinally arranged along each layer of lattice columns of the deep foundation pit, and the steel casing is passed through the casing support.

[0007] The above-mentioned drainage pipe well system suitable for temporary additions in deep foundation pit construction also includes a clay pile heightening platform, which is arranged at the excavation surface at the bottom of the foundation pit and located around the steel casing of the bottom layer. An anti-filtration geotextile is laid on the surface of the clay pile heightening platform, and sandbags are piled on the geotextile.

[0008] The above is applicable to the temporary drainage pipe well system added during the deep foundation pit construction. The clay pile platform is built according to the radius of the cone with the steel casing as the center, which is 1.5 times the radius of the casing. The platform is compacted and the slope of the cone is 1:1.5.

[0009] The above is applicable to the temporary drainage pipe well system added during deep foundation pit construction. The height of the sandbags is calculated according to the most unfavorable jacking force.

[0010] The above-mentioned system is suitable for a temporary drainage pipe well system added during deep foundation pit construction. The steel platform includes a bottom support beam set by an I-beam and a steel plate laid on the bottom support beam. The steel platform is erected on the ground through the bottom support beam.

[0011] The above-mentioned dewatering pipe well system newly added temporarily during deep foundation pit construction is characterized in that: the casing support includes two channel steels welded on both sides of the steel casing, and the two ends of the two channel steels are respectively welded and fixed to the embedded steel bars or planted steel bars of the lattice column.

[0012] The dewatering pipe well system proposed by the present utility model sets a steel platform at the formed lattice column or upper support structure, and then inserts the steel casing pipe into the foundation pit through the steel platform as a support surface facing the foundation pit excavation surface. Subsequently, the bottom of the steel casing pipe is cleared of holes, and finally, a drain pipe is inserted into the steel casing pipe and a pumping device is set up, so as to realize a complete temporary dewatering system that does not conflict with the foundation pit working surface. Description of the Drawings

[0013] Figure 1 It is a layout schematic diagram of the steel platform in the present utility model.

[0014] Figure 2 It is a layout schematic diagram of the clay stacking platform in the present utility model.

[0015] Figure 3 It is a layout schematic diagram of the casing support in the present utility model.

[0016] Figure 4 It is an overall schematic diagram of the present utility model. Detailed Embodiment

[0017] Next, the technical solutions of the embodiments of the present application will be described clearly and completely in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope protected by the present application.

[0018] Such as Figures 1 to 4 , a dewatering pipe well system newly added temporarily during deep foundation pit construction, includes:

[0019] 1. High-altitude steel platform 1:

[0020] Using the existing trestle and support as the bottom support, 3 H700×300×13×24 steel sections are arranged on the upper part of the support, steel plates are laid on the support, the steel plates and the steel sections are welded and fixed by manual arc welding. After the steel plates are laid, 48x3.0 steel pipes are used to set up safety guardrails. The safety guardrails adopt two railings. The middle railing is away from the ground, the upper railing is away from the ground, the distance between the vertical poles, and the height of the toe board.

[0021] 2. Steel casing 2

[0022] The total length, diameter, and wall thickness of the steel casing. First, position the steel casing. After positioning, use a crane to lift a hydraulic vibratory hammer for sinking. During the sinking process, ensure the verticality of the steel casing and the depth of the steel casing embedded in the soil layer (not less than entering the clay layer).

[0023] 3. Clay heap platform 3:

[0024] A clay heap platform is set around the casing at the excavation surface at the bottom of the foundation pit. At the same time, an anti-filter geotextile is added, and sandbags are stacked on the geotextile. The clay heap platform is built in a frustum shape with the casing as the center. The stacking radius is taken as 1.5 + the radius of the casing, and the platform is compacted. The slope of the frustum is 1:1.5. An anti-filter geotextile is laid on the upper part of the frustum and is tightly wound around the casing part with a rope. Sandbags are placed on the geotextile. The height of the sandbags is calculated according to the most unfavorable uplift force h = {(26 - 3) * 10 - (26 - 14.10) * 18} / 17 =, and three layers of sandbags are placed according to the calculation.

[0025] 4. Auxiliary fixing structure 4 of the steel casing:

[0026] Since the pipe well drilling construction process will have vibrations, to prevent the steel casing from tilting, steel profiles are erected at the second support, and at the same time, 2 pieces of 18# channel steel are firmly welded to the steel casing. During welding, the inner wall of the steel casing must not be damaged. Both the steel profiles and the channel steel are welded and fixed to the embedded or planted steel bars of the second support, and the diameter must not be less than.

[0027] The implementation method of the above dewatering pipe well:

[0028] Step 1. Entering and leaving the site, positioning:

[0029] Set up a drilling platform according to the well position on the design institute drawings, and use a crawler GP10 model drill to enter the site. After the platform is checked and calculated, an operating platform and a safety guardrail are set up after it is built, and it is put into use after passing the acceptance.

[0030] When installing the drill, to ensure the verticality of the hole, the machine platform should be installed firmly and horizontally, the big hook should be aligned with the center of the hole, and the big hook, the turntable, and the center of the hole should be in a straight line. Strictly control the opening of the hole. Two drill collars are attached to the connection between the drill bit and the drill pipe, and moreover, the bent drill pipe shall not be lowered into the hole.

[0031] Step 2. Drilling and hole cleaning:

[0032] During drilling, keep the mud specific gravity at 1.1 - 1.2, and try to use the natural mud formation of the formation. During the whole drilling process, it is required to slowly feed after tightening the big hook (always in under-reaming drilling) to avoid the drill string from generating a primary bend, especially at the opening of the hole, the drill pipe on the machine and the water joint should not swing significantly. Each time a drill pipe is drilled, the hole should be reamed once, and the mud cake in the hole should be cleaned before connecting a new drill pipe. After the final hole is drilled, the hole should be thoroughly cleaned until the returned mud does not contain mud cakes and the returned mud does not stick to the hand before lifting the drill.

[0033] Step 3: Lower the well pipe:

[0034] Arrange and combine the well pipes in advance according to the designed well depth. When lowering the pipes, the bottom of all deep wells should be strictly controlled according to the elevation, and the elevation of the wellhead should be kept consistent. The well pipe should be smoothly put into the hole. The two ends of each section of the well pipe should be leveled, and the lower end should have a 45-degree slope angle. When welding, the two sections of the well pipe should be straightened from two directions, and two people should weld symmetrically to ensure that the welding is vertical, complete and without gaps, and to ensure the welding strength to avoid falling off. In order to ensure that the well pipe does not lean against the well wall and to ensure the thickness of the sand filling, add a set of 4 straighteners to the upper and lower parts of the water filter pipe to ensure that the thickness of the annular sand filling gap is not less than, the filter should be brushed clean, the filter aperture is uniform and not less than, and a layer of 50-60 mesh filter is wrapped on the outside. The pipe should be lowered accurately. Fall naturally, turn slightly to fall into place, and do not press down forcefully to avoid damaging the filter structure.

[0035] Step 4: Fill filter material (medium-coarse sand):

[0036] After the density of the diluted mud reaches 1.08, turn down the pump volume, slowly fill the filter material, and measure the height of the filter material top surface as it is filled, and it must not be too high. The sand filling of the pressure relief well should strictly follow the sand filling specifications and grading, the well pipe diameter, the horizontal sand filling thickness should not be less than, and the sand filling height should be strictly in accordance with the design drawings.

[0037] When filling the filter material, adjust the pump volume according to the water return situation at the orifice. During the process of filling the filter material, track the filter material return height. When the filter material is dense to the designed height, fill the hole between the well pipe and the hole wall with clay blocks to the well mouth and compact it to prevent mud and surface sewage from flowing into the well from outside the pipe.

[0038] Step 5: Stop water:

[0039] The pressure relief well is filled with thick high-quality clay on the top of the filter material, and then filled with ordinary clay soil, all the way to the ground, before the air compressor well washing can begin. The upper left and right sides of the drainage well can be filled with ordinary clay soil.

[0040] Step 6: Wash the well:

[0041] For the dewatering deep well, the air compressor well washing method is adopted. It is required to wash the well until the water is clear and the sand is completely removed to ensure the well washing quality. The air compressor is used to pump water for well washing (the air compressor pumps water to blow out the sediment at the bottom of the pipe). The principle is as follows: when the compressed air passes through the air inlet pipe to the lower part of the drain pipe, the drain pipe becomes a gas-water mixture with a density less than that of the muddy water mixture outside the drain pipe. In this way, a pressure difference is generated between the inside and outside of the pipe. The muddy water mixture outside the drain pipe flows into the drain pipe under the action of the pressure difference. Then, the inside of the well pipe becomes a three-phase mixture of gas, water, and soil, and its density decreases with the increase of the air injection volume. The three-phase mixture is continuously carried out of the well, and the soil component in the filter material becomes less and less until it is cleaned. When there is a lot of sediment in the well pipe, the method of "holding one's breath and boiling" can be adopted, that is, repeatedly closing and opening the valve of the gas-water-soil mixture on the outlet pipe to make the water in the well boil to break the adhesion between the mud skin and the sediment filter material until the water discharged from the well pipe changes from turbid to clear and reaches the normal water output. The well washing time is generally 4 to 6 hours.

[0042] Step 7: Lower the pump to pump water:

[0043] Relief well: The pump body should be installed stably, the pump shaft should be vertical, and the drain pipe and the power supply line should be connected for trial pumping to measure the water level in the well and the water level change and flow rate of the observation well.

[0044] It can be seen from the above embodiments that the general idea of this technical solution is to set up a steel platform on the formed lattice column or the upper support structure, and then insert the steel pipe into the foundation pit through the steel platform as a support surface facing the foundation pit excavation surface. Subsequently, the bottom of the steel pipe is cleared, and finally, a drain pipe is inserted into the steel pipe and a pumping device is set up to realize a complete temporary dewatering system that does not conflict with the foundation pit working surface.

[0045] The above are only the embodiments provided by this application and are not used to limit this application. Although this application has been described in detail with reference to the embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A temporary new dewatering pipe well system applicable to deep foundation pit construction, characterized in that: It includes a steel platform, a steel casing, and a casing support. Among them, the steel platform is set on the ground, the casing support is longitudinally arranged along the lattice columns of each layer of the deep foundation pit, and the steel casing is inserted into the casing support.

2. The temporary additional dewatering pipe well system applicable to deep foundation pit construction according to claim 1, characterized in that: It also includes a clay stacking platform, which is set at the excavation surface at the bottom of the foundation pit and is located around the steel casing at the bottom layer. An anti-filter geotextile is laid on the surface of the clay stacking platform, and sandbags are stacked on the geotextile.

3. The temporary newly added dewatering pipe well system applicable to deep foundation pit construction according to claim 2, characterized in that: The clay stacking platform is built in the shape of a frustum of a cone with the steel casing as the center. The stacking radius is taken as 1.5 times the radius of the casing, and the platform is compacted. The slope of the frustum of the cone is set at 1:1.

5.

4. The temporary additional dewatering pipe well system applicable to deep foundation pit construction according to claim 2, wherein: The height of the sandbags is obtained by calculating the most unfavorable uplift force.

5. The temporary additional dewatering pipe well system applicable to deep foundation pit construction according to claim 1, characterized in that: The steel platform includes bottom support beams made of I-beams and steel plates laid on the bottom support beams. The steel platform is erected on the ground through the bottom support beams.

6. The temporary additional dewatering pipe well system applicable to deep foundation pit construction according to claim 1, wherein: The casing support includes two channel steels welded on both sides of the steel casing, and the two ends of the channel steels are respectively welded and fixed to the embedded steel bars or implanted steel bars of the lattice columns.

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