阅读说明：本技术 一种trd工法连续墙与土石围堰结合的复合临时挡水结构物及施工方法 (TRD construction method continuous wall and earth-rock cofferdam combined composite temporary water retaining structure and construction method ) 是由 邓磊 邓漓 周平 刘一宏 张志鹏 姚琦 刘岭楠 颜锦凯 王晗 于 2020-04-10 设计创作，主要内容包括：本发明提供了一种TRD工法连续墙与土石围堰结合的复合临时挡水结构物及施工方法,由土石方围堰、TRD工法连续墙、黏性土填筑区组成。本发明通过建立土石围堰为基础结构,采用内部TRD工法连续墙为芯墙,辅助以顶部回填粘性土,底部视地层情况进行帷幕灌浆的方式形成河(湖)底以上的联合挡水体系,解决河(湖)底高程以上的挡水与河(湖)底高程以下的防渗问题,不仅提高了临建设施的挡水效果,同时降低了拆除的难度,达到节省投资的效果,为针对跨河,跨湖等水面高程以下采用明挖施工的工况进行挡水结构设计实施提供了可行的方案。整个临时挡水结构物相较于其他围堰结构形式,在工期,投资,防渗效果上具有优势。(The invention provides a composite temporary water retaining structure combining a TRD (blast furnace direct grouting) construction method continuous wall and an earth-rock cofferdam and a construction method. The invention adopts the internal TRD construction method continuous wall as the core wall, assists to backfill cohesive soil at the top, and forms a combined water retaining system above the bottom of the river (lake) in a mode that the bottom is subjected to curtain grouting according to stratum conditions, solves the seepage prevention problems of water retaining above the elevation of the bottom of the river (lake) and below the elevation of the bottom of the river (lake), improves the water retaining effect of construction, reduces the difficulty of dismantling, achieves the effect of saving investment, and provides a feasible scheme for designing and implementing the water retaining structure by adopting the working condition of open cut construction below the water surface elevations of river striding, lake striding and the like. Compared with other cofferdam structure forms, the whole temporary water retaining structure has the advantages of construction period, investment and seepage prevention effect.)

1. A TRD construction method continuous wall and earth-rock cofferdam combined composite temporary water retaining structure is characterized by comprising an earth-rock cofferdam, a TRD construction method continuous wall and a cohesive soil filling area; the TRD construction method continuous wall is arranged on the upstream side of the earthwork cofferdam, and the lower end of the TRD construction method continuous wall is lower than the interface of the permeable layer and the impermeable layer; the cohesive soil filling area is located in the earth-rock cofferdam above the TRD construction method continuous wall, and the bottom end of the cohesive soil filling area is in lap joint with the TRD construction method continuous wall.

2. The composite temporary water retaining structure combining the TRD-method continuous wall and the earth-rock cofferdam as recited in claim 1, wherein a riprap desilting area or a geogrid is provided in an area other than 2m from the TRD-method continuous wall at a contact surface of the earth-rock cofferdam and the river bed.

3. The composite temporary water retaining structure combining the TRD-method continuous wall and the earth-rock cofferdam as recited in claim 1, wherein the upper end of the TRD-method continuous wall is higher than the current water level.

4. The composite temporary water retaining structure combining the TRD-method continuous wall and the earth-rock cofferdam as recited in claim 1, wherein the overlapping height of the cohesive soil filling area and the TRD-method continuous wall is not less than 1 m.

5. The construction method of the composite temporary water retaining structure combining the TRD method continuous wall and the earth-rock cofferdam as recited in claim 1, is characterized by comprising the steps of:

(1) before the construction of the earth-rock cofferdam, floating mud in the range of the weir base is removed;

(2) filling an earth-rock cofferdam, and suspending filling of the earth-rock cofferdam when the earth-rock cofferdam is filled to a certain elevation; taking the earth-rock cofferdam with the elevation as a construction platform of the TRD construction method continuous wall, wherein the elevation is higher than the current water level by more than 0.5 m; carrying out site leveling before construction of the continuous wall in the TRD method, wherein a construction access meets the requirements of stable walking and movement of a cutting machine and a crane;

(3) carrying out construction operation on the diaphragm wall in the TRD method, wherein the bottom of the diaphragm wall extends into the impervious layer by more than 0.5m, and the upper end of the diaphragm wall is higher than the current water level;

(4) after the construction of the continuous wall in the TRD construction method, recovering earth-rock cofferdam filling, filling according to a water conservancy calculation result until the water retaining elevation, and synchronously filling a cohesive soil filling area; when the cohesive soil is filled, the elevation of the top of the continuous wall in the TRD construction method is reduced by a certain height to serve as a reference elevation, and the cohesive soil is filled within the range of an opening slope ratio of 1: 0.5-1: 1.

Technical Field

The invention relates to a composite temporary water retaining structure combining a TRD (Trench cutting Re-mixing Deep wall) construction method and an earth-rock cofferdam and a construction method thereof, which are suitable for the field of temporary water retaining design of engineering construction adopting open cut construction below water surface elevations such as river crossing, lake crossing and the like.

Background

In general, tunnel, box culvert, pipeline and comprehensive pipe gallery projects crossing rivers, lakes and the like below water surface elevations need to be provided with temporary water retaining structures at construction sections in an open-cut construction mode so as to guarantee the dry operation environment and construction safety of workers and machines in construction in foundation pits. The foundation pit seepage prevention is one of the key difficulties of the engineering, and an seepage prevention structure needs to be arranged on the cofferdam and the weir base to form a closed seepage prevention system so as to ensure the safety of the foundation pit.

Aiming at the special working condition of open cut construction below the water surface elevation, the river channel and the internal lake have the water retaining problem above the river (lake) bottom elevation and the seepage prevention problem below the river (lake) bottom elevation. The existing temporary water retaining structure comprises an earth-rock cofferdam, a concrete cofferdam, a grout stone cofferdam and a steel sheet pile cofferdam, and the existing temporary water retaining structure has application defects aiming at the working conditions. Wherein the earth-rock cofferdam can only solve the problem of water retaining at the upper part; the masonry cofferdam construction efficiency is low, the cost is higher, and a dry working environment must be created during the self construction; the underwater pouring mode of the concrete cofferdam has the advantages that the quality is not easy to guarantee, the construction cost is high, the underwater pouring mode is difficult to dismantle, the underwater pouring mode is generally used for a permanent water retaining structure, meanwhile, the concrete cofferdam generally needs to act on bedrock, and the underwater pouring mode is not suitable for the environment with more sludge, such as a river channel or a lake; the steel sheet pile cofferdam has higher requirement on the uniformity of the stratum, directly influences the verticality control of steel sheet construction when the stratum changes, has weak adaptability to broken and pebble stratums, can not be driven by the steel sheet, and has larger influence on the price of steel products by the market.

Therefore, how to design a temporary water retaining structure for construction, which can retain water above the bottom of a river (lake) and prevent seepage below the bottom elevation, is a problem to be solved urgently to ensure the construction safety under the working conditions.

Disclosure of Invention

The invention aims to provide a temporary water retaining structure for construction, which can retain water above the bottom of a river (lake) and prevent seepage below the bottom elevation. Therefore, the invention adopts the following technical scheme:

a composite temporary water retaining structure combining a TRD construction method continuous wall and an earth-rock cofferdam; the construction method is characterized by comprising an earth-rock square cofferdam, a TRD construction method continuous wall and a cohesive soil filling area; the TRD construction method continuous wall is arranged on the upstream side of the earthwork cofferdam, and the lower end of the TRD construction method continuous wall is lower than the interface of the permeable layer and the impermeable layer; the cohesive soil filling area is located in the earth-rock cofferdam above the TRD construction method continuous wall, and the bottom end of the cohesive soil filling area is in lap joint with the TRD construction method continuous wall.

Compared with a concrete underground continuous wall, the structure has lower requirement on the bearing capacity of the foundation, and the bottom of the continuous wall in the TRD construction method only needs to extend into the impervious bed by more than 0.5m on the basis of meeting the bearing capacity of the foundation. Therefore, technical support is provided for rapidly removing temporary water retaining structures and reducing engineering investment in future.

Furthermore, a rock throwing and silt squeezing area or a geogrid is arranged on the contact surface of the earth-rock square cofferdam and the riverbed in the area 2m away from the TRD construction method continuous wall.

Further, the upper end of the TRD construction method continuous wall is higher than the current water level.

Further, the lap joint height of the cohesive soil filling area and the TRD construction method continuous wall is not less than 1 m.

The bottom end of the TRD construction method continuous wall can also increase the seepage-proofing capacity of the curtain grouting construction reinforcing structure.

The invention also aims to provide a construction method of the composite temporary water retaining structure combining the TRD construction method continuous wall and the earth-rock cofferdam, which comprises the following steps:

(1) before the construction of the earth-rock cofferdam, floating mud in the range of the weir base is removed;

(2) filling an earth-rock cofferdam, and suspending filling of the earth-rock cofferdam when the earth-rock cofferdam is filled to a certain elevation; taking the earth-rock cofferdam with the elevation as a construction platform of the TRD construction method continuous wall, wherein the elevation is higher than the current water level by more than 0.5 m; carrying out site leveling before construction of the continuous wall in the TRD method, wherein a construction access meets the requirements of stable walking and movement of a cutting machine and a crane;

(3) carrying out construction operation on the diaphragm wall in the TRD method, wherein the bottom of the diaphragm wall extends into the impervious layer by more than 0.5m, and the upper end of the diaphragm wall is higher than the current water level;

(4) after the construction of the continuous wall in the TRD construction method, recovering earth-rock cofferdam filling, filling according to a water conservancy calculation result until the water retaining elevation, and synchronously filling a cohesive soil filling area; when the cohesive soil is filled, the elevation of the top of the continuous wall in the TRD construction method is reduced by a certain height to serve as a reference elevation, and the cohesive soil is filled within the range of an opening slope ratio of 1: 0.5-1: 1.

The elevation of the construction platform of the continuous wall in the TRD construction method can be adjusted according to actual conditions, but the construction platform and the operation environment are ensured to meet the construction requirements of the construction method.

The filling range of the cohesive soil at the top end of the continuous wall in the TRD construction method can be adjusted according to the actual investment condition, and the slope ratio of the opening line and the filling bottom elevation can be adjusted.

The invention adopts the internal TRD construction method continuous wall as the core wall, assists to backfill cohesive soil at the top, and forms a combined water retaining system above the bottom of the river (lake) in a mode that the bottom is subjected to curtain grouting according to stratum conditions, solves the seepage prevention problems of water retaining above the elevation of the bottom of the river (lake) and below the elevation of the bottom of the river (lake), improves the water retaining effect of construction, reduces the difficulty of dismantling, achieves the effect of saving investment, and provides a feasible scheme for designing and implementing the water retaining structure by adopting the working condition of open cut construction below the water surface elevations of river striding, lake striding and the like. Compared with other cofferdam structure forms, the whole temporary water retaining structure has the advantages of construction period, investment and seepage prevention effect.

Drawings

Fig. 1 is a sectional view of a composite temporary water retaining structure combining a diaphragm wall and an earth-rock cofferdam according to the TRD method of the present invention.

Detailed Description

Reference is made to the accompanying drawings. The invention provides a temporary composite water retaining structure combining a TRD (blast furnace direct grouting) construction method continuous wall and an earth-rock cofferdam, which comprises an earth-rock square cofferdam 1, a TRD construction method continuous wall 2 and a cohesive soil filling area 3, wherein the TRD construction method continuous wall 2 is arranged on the side of the earth-rock square cofferdam 1, which is deviated to the upstream. The concrete construction process of the invention is as follows:

(1) before the construction of the earth-rock cofferdam, floating mud (0.5m thick) in the range of the weir base is removed to ensure that the cofferdam is contacted with the riverbed, the weir base is further stabilized by adopting a rubble-throwing and silt-squeezing mode in local areas, and the reference numeral 11 is a rubble-throwing and silt-squeezing area (0.5m thick). The integral inclination angle of the contact surface is not more than 2 degrees. In order to avoid the influence of the geogrid and the rubble extrusion on the construction of the TRD construction method continuous wall, the geogrid and the rubble extrusion are not arranged within the range of 2m on the two sides of the TRD construction method continuous wall.

(2) The earth-rock cofferdam is uniformly and symmetrically filled with earth-rock squares in a layered manner, and the joint of the earth-rock cofferdam and the bank slope is used for cleaning weeds, rock blocks, construction wastes and the like, so that a leakage channel is prevented from being formed, and the seepage-proof body of the cofferdam is ensured to be tightly connected with the bank slope. The earth-rock cofferdams are filled to the height h1 of the TRD-method continuous wall construction platform 12 in a layered mode, the height h1 is higher than the current water level by more than 0.5m, and an operation environment is provided for the TRD-method continuous wall construction. Site leveling is required to be carried out before construction of the continuous wall in the TRD method, and the construction access meets the requirements of stable walking, movement and the like of a cutting machine and a crane.

(3) A cutting machine and a crane are utilized to carry out TRD method continuous wall construction operation, the bottom of the continuous wall should extend into the impervious bed by more than 0.5m, and the reference numeral 101 is an interface of the pervious bed and the impervious bed. And curtain grouting 21 is carried out according to the condition of the bottom stratum to enhance the anti-seepage effect.

(4) The water retaining height requirement of the water retaining building is determined according to the hydraulic calculation result or data provided by design, generally not lower than the sum of the still water level and the wave height of the design flood and the safe heightening of the top of the water retaining building, wherein the height of a 3-level building is 0.7m, and the height of a 4-level building is 0.5m according to the level of the water retaining building. And calculating to obtain the top standard height h2 of the earth-rock cofferdam 1.

(5) And uniformly and symmetrically filling the TRD construction method continuous wall construction platform 12 to the calculated cofferdam top height h2 in layers. Filling cohesive soil synchronously; the cohesive soil filling area 3 is located in the earth-rock cofferdam 1 above the TRD construction method continuous wall 2, the bottom end of the cohesive soil filling area 3 is overlapped with the TRD construction method continuous wall 2, and in order to improve the seepage-proofing effect, the bottom elevation h3 of the cohesive soil filling area 3 is lower than the TRD construction method continuous wall construction platform 12 (in order to ensure that a complete and closed seepage-proofing system is formed, the overlapping height is generally not lower than 1m in engineering practice). And filling cohesive soil within the range of an opening slope ratio of 1: 0.5-1: 1 by taking the bottom elevation h3 of the cohesive soil filling area 3 as a reference elevation.

Wherein, below the elevation of the platform 12, original soil and stones are dug out at the joint of the cohesive soil backfilling area 3 and the continuous wall 2 in the TRD construction method, and then the cohesive soil is backfilled and compacted.

(6) And after the composite water retaining structure is finished, constructing necessary slope protection measures. Wherein, a drainage ditch 41 is constructed on the slope toe of the back water surface, and concrete 42 is sprayed on the slope surface by hanging a net; the slope toe of the upstream face adopts a stone presser foot 51, and the slope is firmly pressed by bagged soil or stones after being paved by geotextile 52.

The above description is only an embodiment of the present invention, and the technical features of the present invention are not limited thereto, and any changes or modifications within the field of the present invention by those skilled in the relevant art are covered by the protection scope of the present invention.