Composite waterproof curtain

Abstract

The utility model belongs to the field of municipal engineering, and provides a combined type waterproof curtain which comprises a high-pressure grouting body and an annular waterproof curtain surrounding the outer side of a deep foundation pit. The bottom of the deep foundation pit extends downwards into a moderately weathered rock stratum, a plurality of high-pressure grouting holes are formed in the moderately weathered rock stratum in the circumferential direction of the deep foundation pit at intervals, and the high-pressure grouting bodies are filled in the high-pressure grouting holes and fracture surfaces of surrounding rock stratums; the annular waterproof curtain comprises a plurality of high-pressure jet grouting piles, the high-pressure jet grouting piles are arranged in the circumferential direction of the deep foundation pit, every two adjacent high-pressure jet grouting piles are partially overlapped, and the bottoms of the high-pressure jet grouting piles downwards penetrate through the strongly-weathered rock stratum and stretch into high-pressure grouting bodies of the moderately-weathered rock stratum. According to the combined type waterproof curtain, two water stopping measures are adopted for achieving the synergistic effect, water seepage of the foundation pit is effectively prevented, the construction safety of the foundation pit is guaranteed, the combined type waterproof curtain is suitable for the rock-soil mixed deep foundation pit with the upper portion being a thick soil layer and the lower portion being a rock stratum, and the good foundation pit water stopping effect can be achieved.

Description

Technical Field

[0001] The utility model belongs to the field of municipal engineering, and specifically relates to a composite water-stopping curtain. Background Art

[0002] It is very important to control groundwater during the excavation of deep foundation pits. Common groundwater control methods in engineering can be summarized as "lowering, draining, blocking, and intercepting". In densely built areas such as cities, the use of precipitation and drainage measures has a greater impact on the surrounding environment, so it is more recommended to use water blocking and interception solutions to control groundwater in foundation pits.

[0003] Common foundation pit water-stop curtain technologies include underground continuous walls, Larsen steel sheet piles, row pile curtains, high-pressure rotary jet pile curtains, cement-soil mixing pile curtains, etc. High-pressure rotary jet pile curtains are widely used due to their small footprint, low vibration and noise, and fast construction speed. High-pressure rotary jet pile curtains are mainly used in soil layers. Their main principle is to use high-speed jet cement slurry or water flow to cut the soil and mix the crushed soil with cement slurry to form a cement-soil seepage barrier. Due to the characteristics of its construction process, high-pressure rotary jet pile curtains are difficult to apply to rock formations, but when the depth of a deep foundation pit is deep, it may enter the underlying rock formation (medium weathered rock formation). The underlying rock formation often has crack surfaces, and groundwater can easily enter the deep foundation pit through the crack surface, thereby affecting the construction safety of the deep foundation pit. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a composite water-stopping curtain, which is suitable for a rock-soil mixed deep foundation pit with a thicker soil layer on the upper part and a rock layer on the lower part, and can achieve a better foundation pit water-stopping effect.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a composite water-stop curtain, including a high-pressure grouting body and an annular water-stop curtain surrounding the outer side of a deep foundation pit;

[0006] The bottom of the deep foundation pit extends downward into the medium weathered rock layer, and a plurality of high pressure grouting holes are arranged in the medium weathered rock layer along the circumference of the deep foundation pit at intervals, and the high pressure grouting body is filled in the high pressure grouting holes and the fracture surfaces of the surrounding rock layers;

[0007] The annular water-stop curtain includes a plurality of high-pressure rotary jet piles, which are arranged circumferentially along the deep foundation pit, and two adjacent high-pressure rotary jet piles partially overlap. The top of the high-pressure rotary jet pile is located at the top of the soil layer, and the bottom of the high-pressure rotary jet pile passes downward through the strongly weathered rock layer and extends into the high-pressure grouting body of the medium weathered rock layer.

[0008] Preferably, the bottom of the high-pressure grouting hole is lower than the bottom of the deep foundation pit.

[0009] Preferably, the bottom of the high-pressure jet jet pile extends into the high-pressure grouting body by at least 1 m.

[0010] Preferably, the diameter of the high-pressure jet jet pile is 700 mm.

[0011] Preferably, the overlapping thickness of two adjacent high-pressure jet jet piles is 200 mm.

[0012] Preferably, the high-pressure grouting hole has a diameter of 100 mm.

[0013] Preferably, adjacent high-pressure grouting holes are spaced 1000 mm apart.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] The utility model provides a composite water-stop curtain, which can enhance the seepage-proof performance of the surrounding rock mass by injecting grout into the high-pressure grouting holes so that the slurry fills the cracks, joints, layers and other structural surfaces in the surrounding rock mass, and effectively protects the deep foundation pit in the medium-weathered rock layer. Then, a plurality of high-pressure rotary jet piles are arranged to bite and form an annular water-stop curtain, which can effectively protect the deep foundation pit in the soil layer and the strongly weathered rock layer. The two water-stopping measures work together to effectively prevent water seepage in the foundation pit and ensure the safety of the foundation pit construction. In addition, the high-pressure rotary jet piles extend downward into the high-pressure grouting body to ensure the anti-seepage performance of the joints. It is suitable for rock-soil mixed deep foundation pits with a thicker soil layer on the upper part and a rock layer on the lower part, and can achieve a better foundation pit water-stopping effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic cross-sectional structure diagram of a composite water-stop curtain provided in an embodiment of the utility model;

[0017] Figure 2 A schematic diagram of a partial top view of an annular water-stopping curtain of a composite water-stopping curtain provided in an embodiment of the utility model;

[0018] Figure 3 A schematic diagram of the top view structure of a high-pressure grouting hole of a composite water-stop curtain provided in an embodiment of the utility model.

[0019] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0020] 1. High-pressure grouting body; 2. High-pressure jet jet piles; 3. Soil layer; 4. Strongly weathered rock layer; 5. Moderately weathered rock layer; 6. Deep foundation pit; 7. High-pressure grouting hole; 8. Annular water-stop curtain. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0022] It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrally formed structure. For ordinary technicians in this field, the specific meanings of such terms in this patent can be understood according to specific circumstances.

[0023] like Figure 1-3 As shown, the deep foundation pit 6 passes downward through the soil layer 3, the strongly weathered rock layer 4 and into the medium weathered rock layer 5. Obviously, the existing single foundation pit water-stopping measures cannot achieve a good foundation pit water-stopping effect. In order to solve the above problems, this embodiment provides a composite water-stopping curtain, including a high-pressure grouting body 1 and three layers of annular water-stopping curtains 8 surrounding the outside of the deep foundation pit 6.

[0024] Two layers of holes are provided in the medium-weathered rock layer 5, one layer of holes includes a plurality of vertically arranged high-pressure grouting holes 7, and the plurality of high-pressure grouting holes 7 are arranged at intervals along the circumference of the deep foundation pit 6. The first layer of holes surrounds the outside of the deep foundation pit 6, and the second layer of holes surrounds the outside of the first layer of holes. The high-pressure grouting body 1 is filled in the high-pressure grouting holes 7 and the fracture surfaces of the surrounding rock layers, that is, the high-pressure grouting body 1 includes a portion filled in the high-pressure grouting holes 7 and a portion filled in the surrounding fracture surfaces, that is, the high-pressure grouting body 1 is formed by grouting into the high-pressure grouting holes 7, and the slurry can be filled into the structural surfaces such as fractures, joints and layers in the surrounding rock mass to enhance the seepage barrier performance of the surrounding rock mass.

[0025] The annular water-stop curtain 8 can be a circular, rectangular or other structure, and is arranged according to the shape of the deep foundation pit 6. The annular water-stop curtain 8 includes a plurality of vertically arranged high-pressure rotary jet piles 2, and the plurality of high-pressure rotary jet piles 2 are arranged circumferentially along the deep foundation pit 6. Two adjacent high-pressure rotary jet piles 2 partially overlap, that is, the construction ranges of two adjacent high-pressure rotary jet piles 2 partially overlap, so that the two adjacent high-pressure rotary jet piles 2 will partially overlap after being formed. The first layer of the annular water-stop curtain 8 surrounds the outside of the deep foundation pit 6, the second layer of the annular water-stop curtain 8 surrounds the outside of the first layer of the annular water-stop curtain 8, and the second layer of the annular water-stop curtain 8 partially overlaps with the first layer of the annular water-stop curtain 8, the third layer of the annular water-stop curtain 8 surrounds the outside of the second layer of the annular water-stop curtain 8, and the third layer of the annular water-stop curtain 8 partially overlaps with the second layer of the annular water-stop curtain 8, and the three layers of the annular water-stop curtain 8 together constitute a complete annular seepage barrier.

[0026] Among them, the top of the high-pressure rotary jet pile 2 is located at the top of the soil layer 3, and the bottom of the high-pressure rotary jet pile 2 passes downward through the strongly weathered rock layer 4 and extends into the high-pressure grouting body 1 of the medium-weathered rock layer 5, which can ensure the anti-seepage performance of the junction between the bottom of the high-pressure rotary jet pile 2 and the high-pressure grouting body 1.

[0027] In summary, the composite water-stop curtain provided in this embodiment can enhance the seepage-proof performance of the surrounding rock mass by grouting into the high-pressure grouting holes 7 so that the slurry is filled into the cracks, joints, layers and other structural surfaces in the surrounding rock mass, and effectively protect the deep foundation pit in the medium-weathered rock layer. Then, by setting a plurality of the high-pressure rotary jet piles 2 to bite into each other to form an annular water-stop curtain 8, the deep foundation pit in the soil layer and the strongly weathered rock layer can be effectively protected. The two water-stopping measures work together to effectively prevent water seepage in the foundation pit and ensure the safety of the foundation pit construction. In addition, the high-pressure rotary jet piles 2 extend downward into the high-pressure grouting body 1 to ensure the anti-seepage performance at the joint. It is suitable for a rock-soil mixed deep foundation pit with a thicker soil layer on the upper part and a rock layer on the lower part, and can achieve a better foundation pit water-stopping effect.

[0028] In this embodiment, the bottom of the high-pressure grouting hole 7 is lower than the bottom of the deep foundation pit 6 , which can prevent moisture from seeping into the deep foundation pit 6 from below the high-pressure grouting body 1 .

[0029] In this embodiment, the bottom of the high-pressure rotary jet pile 2 extends downward into the medium-weathered rock layer 5 by 1m, and the top of the high-pressure grouting body 1 is originally flush with the top of the medium-weathered rock layer 5, that is, the bottom of the high-pressure rotary jet pile 2 extends into the high-pressure grouting body 1 by 1m, which can ensure the anti-seepage performance of the joint.

[0030] It should be noted that when constructing the high-pressure jet grouting pile 2, the overlapping portion of the high-pressure grouting body 1 will be knocked out first, and then the high-pressure jet grouting pile 2 will be constructed.

[0031] like Figure 2 As shown, the pile diameter of the high-pressure rotary jet pile 2 can be 700mm. The overlapping thickness of two adjacent high-pressure rotary jet piles 2 can be 200mm. The overlapping thickness of two adjacent layers of the annular water-stop curtain 8 can be 500mm. For example, the radial spacing distance between the high-pressure rotary jet piles 2 of the third layer of the annular water-stop curtain 8 and the high-pressure rotary jet piles 2 of the second layer of the annular water-stop curtain 8 is 500mm.

[0032] like Figure 3 As shown, the diameter of the high pressure grouting hole 7 can be 100 mm. The interval between adjacent high pressure grouting holes 7 is 1000 mm. The spacing between the two layers of holes can be 1000 mm.

[0033] In addition, the construction method of the composite water-stop curtain provided in this embodiment may include the following steps:

[0034] Step 1: Drilling of high-pressure grouting holes 7, with a hole diameter of 100 mm, three-sequence construction, a drilling spacing of 1 m, and arranging double rows of holes, i.e. two layers of holes, in a plum blossom shape;

[0035] Step 2: After drilling is completed, wash the entire hole before grouting. After the clean water flows out of the hole for a period of not less than 3 minutes, grouting can be performed.

[0036] Step 3, high-pressure grouting, using a bottom-up circulation grouting method, the grouting section length is no more than 10 meters (for example, 5 meters), the grouting is divided into three sequences according to the principle of sequence encryption, and the grouting construction is carried out in sections in each hole;

[0037] Step 4: During high-pressure grouting, the grouting slurry should be changed from dilute to concentrated step by step. The water-cement ratio should be set at 2:1 and then stopped at 0.6:1. If the grouting pressure remains unchanged and the injection rate continues to decrease, or the injection rate remains unchanged but the grouting pressure keeps increasing, the water-cement ratio should not be changed. When the injection volume of a certain ratio slurry reaches more than 300L, or the grouting will reach 1h, but the grouting pressure and injection rate have not changed, change to a concentrated water-cement ratio slurry of the first level. When the injection rate is greater than 30L / min, it can be thickened by leaps and bounds according to the actual situation on site.

[0038] Step 5: At the maximum design pressure of the grouting section, the injection rate is not more than 0.4L / min, and the grouting is continued for 60min. When the injection rate is not more than 1L / min, the grouting is continued for 90min. The hole is sealed by the full hole grouting sealing method.

[0039] Step 6, high pressure jet grouting pile 2 is measured and laid out, the hole position is determined, the drilling rig is used for drilling, and the mud wall rotary drilling is adopted. The pile diameter of the high pressure jet grouting pile 2 is 700mm and the overlap width is 200mm;

[0040] Step 7, after the high-pressure jet pipe is lowered to the designed depth, the jet pipe is rotated in situ at a predetermined rotation speed. The jet pipe can be lifted only when the specific gravity, displacement and wind pressure of the cement slurry reach the predetermined values. During the jet grouting construction process, the amount of grouting from the orifice is observed at any time. It is normal for the amount of grouting to be about 20% of the grouting amount. When there are large gaps in some hole sections that cause no grouting, the grouting amount should be increased, and the jet should not be lifted and sprayed statically until the gaps are filled before lifting and spraying.

[0041] Step 8: Jet grouting piles. The high-pressure jet grouting solidifies into a cylindrical shape. Adjacent piles overlap and interlock with each other to form a seepage barrier. The depth of high-pressure jet grouting must enter the lower weathered rock layer for at least 1m to ensure the anti-seepage performance of the joints.

[0042] The mechanisms, components and parts not specifically described in the present invention are all existing structures in the prior art and can be directly purchased from the market.

[0043] In the description of the present utility model, it should be understood that the terms "upper", "lower", "left", "right", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, and a specific direction structure and operation, and therefore, cannot be understood as a limitation on the present utility model. In addition, "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0044] The above is only a preferred embodiment of the utility model, and is not intended to limit the protection scope of the utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A composite water-stop curtain, characterized in that: It comprises a high-pressure grouting body (1) and an annular water-stopping curtain (8) surrounding the outside of a deep foundation pit (6); The bottom of the deep foundation pit (6) extends downward into the medium weathered rock layer (5), and a plurality of high pressure grouting holes (7) are arranged at intervals along the circumference of the deep foundation pit (6) in the medium weathered rock layer (5), and the high pressure grouting body (1) is filled in the high pressure grouting holes (7) and the crack surfaces of the surrounding rock layers; The annular water-stop curtain (8) comprises a plurality of high-pressure jet grouting piles (2), which are arranged circumferentially along the deep foundation pit (6), and two adjacent high-pressure jet grouting piles (2) partially overlap, and the top of the high-pressure jet grouting pile (2) is located at the top of the soil layer (3), and the bottom of the high-pressure jet grouting pile (2) passes downward through the strongly weathered rock layer (4) and extends into the high-pressure grouting body (1) of the medium weathered rock layer (5).

2. A composite water-stop curtain according to claim 1, characterized in that: The bottom of the high-pressure grouting hole (7) is lower than the bottom of the deep foundation pit (6).

3. The composite water-stop curtain according to claim 1, characterized in that: The bottom of the high-pressure jet grouting pile (2) extends into the high-pressure grouting body (1) by at least 1 m.

4. The composite water-stop curtain according to claim 1, characterized in that: The diameter of the high-pressure jet-jet pile (2) is 700 mm.

5. The composite water-stop curtain according to claim 1, characterized in that: The overlapping thickness of two adjacent high-pressure jet-jet piles (2) is 200 mm.

6. The composite water-stop curtain according to claim 1, characterized in that: The high-pressure grouting hole (7) has a diameter of 100 mm.

7. The composite water-stop curtain according to claim 1, characterized in that: The adjacent high-pressure grouting holes (7) are spaced 1000 mm apart.

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