阅读说明：本技术 一种沙洲桥下的下沉式道路施工方法 (Construction method of sunken road under sandbar bridge ) 是由 夏志聪 马越 张志海 赵海莲 夏勇 于 2021-09-27 设计创作，主要内容包括：一种沙洲桥下的下沉式道路施工方法,涉及道路施工领域。沙洲桥下的下沉式道路施工方法是测量放样出道路边线、下沉式道路两边开挖放坡线、倾斜水泥搅拌桩机站位线、止水帷幕线及点位；使用挖机由两端向倾斜水泥搅拌桩机站位线进行下沉式道路开挖；在倾斜水泥搅拌桩机站位线上无缝密布桩位,随后依次向水平方向搅拌形成改良土层；对改良土层养护后施工止水帷幕墙和下沉式道路的道路底基层两侧排水边沟明排,随后在改良土层内进行抗浮锚杆施工,对道路底基层进行清理后进行积水边沟施工、伸缩缝施工、道路面层施工、外墙防水施工、外墙回填施工。沙洲桥下的下沉式道路施工方法能够在施工净空不足和地下水位高的情况下稳固土体并提高地基承载力。(A sinking type road construction method under a sandbar bridge relates to the field of road construction. The construction method of the sunken road under the sandbar bridge comprises the steps of measuring a lofting road side line, excavating slope lines on two sides of the sunken road, inclining a cement mixing pile machine station line, a waterproof curtain line and point positions; carrying out sinking type road excavation from two ends to the station line of the inclined cement mixing pile machine by using an excavator; seamlessly and densely distributing pile positions on the station line of the inclined cement mixing pile machine, and then sequentially mixing towards the horizontal direction to form an improved soil layer; construction of a waterproof curtain wall and open drainage of drainage side ditches on two sides of a road subbase layer of the sunken road after maintenance of the improved soil layer, then construction of an anti-floating anchor rod in the improved soil layer, and after cleaning of the road subbase layer, construction of water accumulation side ditches, construction of expansion joints, construction of a road surface layer, waterproof construction of an outer wall and backfill of the outer wall are carried out. The sinking type road construction method under the sandbar bridge can stabilize soil and improve foundation bearing capacity under the conditions of insufficient construction clearance and high underground water level.)

1. A construction method of a sunken road under a sandbar bridge is characterized by comprising the following steps:

measuring a lofting road side line, a slope line excavated at two sides of a sunken road, an inclined cement mixing pile machine station line, a water-stop curtain line and point positions;

in the dry season, excavating machines are used for excavating sunken roads from two ends to the station line of the inclined cement mixing pile machine, soil below a bridge is reserved as a pre-pressing layer in advance, and a safe and stable side slope is formed by slope collection of soil in front of an operation surface;

seamlessly and densely distributing pile positions on the station line of the inclined cement mixing pile machine, synchronously and symmetrically constructing from two sides of the bridge during operation, jumping piles from one side of the bridge to the side close to the water surface, constructing each pile position vertically, and then sequentially mixing towards the horizontal direction to form an improved soil layer;

after the improved soil layer is maintained for more than 7 days, excavating the un-excavated soil body below the bridge, and constructing the soil body on the near water surface to form an inclined waterproof curtain wall;

maintaining the improved soil layer for more than 14 days, excavating the roadbed of the sunken road, excavating the drainage ditch open rows along the two sides of the improved soil layer after excavating to the road subbase layer, then constructing anti-floating anchor rods in the improved soil layer,

and cleaning the road subbase, finding and repairing, leveling and performing waterproof construction, and then performing ponding side ditch construction, expansion joint construction, road surface layer construction, outer wall waterproof construction and outer wall backfilling construction of the sunken road.

2. The method of constructing a sunken road under a sandbar bridge as claimed in claim 1, wherein the inclined cement mixing pile machine station line is provided at an expansion joint of the sunken road, and is spaced from the sandbar bridge by a distance of 3m or more.

3. The method of constructing a sunken road under a sandbar bridge according to claim 1, wherein when a sunken road is excavated from both ends to the inclined cement mixing pile station line using an excavator, a distance between an excavated surface and a bottom surface of a roadbed is kept to be 50cm or more as a pre-stressed layer, and it is ensured that no open water is found at the bottom of the excavated surface of the inclined cement mixing pile station line.

4. The method of constructing a sunken road under a sandbar bridge as claimed in claim 1, wherein the construction interval time between adjacent pile positions is 8 hours or less when the piles are jumped from one side of the bridge to the side close to the water surface, and the cement incorporation amount of the pile positions is 12-18% of the amount of the soil to be reinforced by dividing the construction interval time into 3-4 steps of speed change according to the density change of the repeatedly rotated parts when each pile position is subjected to the rotary spraying construction.

5. The method of constructing a sunken road under a sandbar bridge according to claim 1, wherein the core strength of the upgraded soil layer is not less than C15, and each side edge of the upgraded soil layer is more than 20cm beyond an outer wall of the sunken road.

6. The method of constructing a sunken road under a sandbar bridge of claim 1, wherein the waterproof curtain wall is formed of double rows of piles, the angle of inclination of the waterproof curtain wall is 15-75 degrees, and the minimum vertical distance of the wall of the waterproof curtain wall from the ascending line of the river levee is 2m or more.

Technical Field

The application relates to the field of road construction, in particular to a sinking type road construction method under a sandbar bridge.

Background

The problems of insufficient construction clearance, high subgrade underground water level, weak foundation, bridge protection close to construction, high difficulty in stopping precipitation when approaching water and the like are often encountered in the construction process of bridge underpass sinking road engineering.

Under the condition of insufficient construction clearance, a method for reducing the standard height of an excavated foundation is adopted, but the method cannot be selected due to the fact that the underground water level is high, the foundation is soft and is close to a pier; in the case of high underground water level and high difficulty in stopping precipitation before water, a steel sheet pile or a cast-in-place pile is adopted to form a water-stopping curtain and then a well point precipitation mode is performed, but the operation clearance is insufficient and cannot be performed; in the case of weak foundation, methods such as replacement filling, cement mixing piles, gravel piles, grouting and the like are usually adopted, but the methods cannot be carried out due to insufficient clearance and incapability of forming holes in the weak foundation; in the face of bridge protection close to construction, a reinforcing measure for a bridge pile foundation is usually taken, but in the face of insufficient bridge clearance, soft foundation, high underground water level and the like, a stable protection measure cannot be formed. Therefore, under the condition of comprehensive superposition of multiple circumstances, due to the consideration of adverse factors such as great quality and safety influence, various measures required to be taken, complex construction procedures, long construction period and the like, only other modes such as viaducts, clearance reduction and restriction and the like can be taken.

Disclosure of Invention

The application aims to provide a construction method of a sunken road under a sandbar bridge, which can stabilize a soil body and overcome the defect of insufficient bearing capacity of a foundation at the same time, and can perform sunken road soft foundation treatment construction under the conditions of insufficient construction clearance under the bridge and high underground water level.

The embodiment of the application is realized as follows:

the embodiment of the application provides a construction method of a sunken road under a sandbar bridge, which comprises the following steps:

measuring a lofting road side line, a slope line excavated at two sides of a sunken road, an inclined cement mixing pile machine station line, a water-stop curtain line and point positions;

in the dry season, a digger is used for carrying out sinking type road excavation from two ends to the line of the inclined cement mixing pile machine station, soil under a bridge is reserved as a pre-pressing layer in advance, and a safe and stable side slope is formed by slope collection of soil in front of an operation surface;

seamlessly and densely distributing pile positions on the station position line of the inclined cement mixing pile machine, synchronously and symmetrically constructing from two sides of a bridge during operation, jumping piles from one side of the bridge to the side close to the water surface, constructing each pile position vertically, and then sequentially mixing towards the horizontal direction to form an improved soil layer;

after the improved soil layer is maintained for more than 7 days, excavating the un-excavated soil body below the bridge, and constructing the soil body on the near water surface to form an inclined waterproof curtain wall;

maintaining the improved soil layer for more than 14 days, excavating the roadbed of the sunken road, excavating the drainage ditch open rows along the two sides of the improved soil layer after excavating the roadbed of the road, then constructing anti-floating anchor rods in the improved soil layer,

cleaning the road subbase, finding and repairing, leveling, performing waterproof construction, and then performing ponding side ditch construction, expansion joint construction, road surface layer construction, outer wall waterproof construction and outer wall backfilling construction of the sunken road.

In some optional embodiments, the inclined cement mixing pile machine station line is arranged at the expansion joint of the sunken road, and the distance between the inclined cement mixing pile machine station line and the sandbank bridge is more than 3 m.

In some optional embodiments, when the excavator is used for excavating a sunken road from two ends to the inclined cement mixing pile machine station line, the distance between an excavation finished surface and the bottom surface of the roadbed is reserved as a pre-pressing layer, and underground open water is not seen at the bottom of the excavation finished surface of the inclined cement mixing pile machine station line.

In some optional embodiments, the construction interval time of adjacent pile positions is below 8h when the pile jumping construction is carried out from one side of the bridge to the side close to the water surface, and the speed change of each pile position is divided into 3-4 steps according to the density change of a repeated rotating part when the rotary spraying construction is carried out, so that the cement mixing amount of the pile positions is 12-18% of the reinforced soil amount.

In some alternative embodiments, the coring strength of the upgraded soil layer is ≧ C15, and each side edge of the upgraded soil layer extends more than 20cm beyond the outer wall of the sunken road.

In some optional embodiments, the waterproof curtain wall is formed by double rows of piles, the inclination angle of the waterproof curtain wall is 15-75 degrees, and the minimum vertical distance between the wall body of the waterproof curtain wall and the upslope line of the river dike is more than 2 m.

The beneficial effect of this application is: the method for constructing the sunken road under the sandbar bridge comprises the following steps: measuring a lofting road side line, a slope line excavated at two sides of a sunken road, an inclined cement mixing pile machine station line, a water-stop curtain line and point positions; in the dry season, a digger is used for carrying out sinking type road excavation from two ends to the line of the inclined cement mixing pile machine station, soil under a bridge is reserved as a pre-pressing layer in advance, and a safe and stable side slope is formed by slope collection of soil in front of an operation surface; seamlessly and densely distributing pile positions on the station position line of the inclined cement mixing pile machine, synchronously and symmetrically constructing from two sides of a bridge during operation, jumping piles from one side of the bridge to the side close to the water surface, constructing each pile position vertically, and then sequentially mixing towards the horizontal direction to form an improved soil layer; after the improved soil layer is maintained for more than 7 days, excavating the un-excavated soil body below the bridge, and constructing the soil body on the near water surface to form an inclined waterproof curtain wall; maintaining the improved soil layer for more than 14 days, excavating the roadbed of the sunken road, excavating the water collecting and draining ditches along two sides of the improved soil layer after excavating to the road subbase layer, then constructing anti-floating anchor rods in the improved soil layer, cleaning the road subbase layer, finding and supplementing leveling and waterproof construction, and then constructing the water accumulating side ditches, the expansion joints, the road surface layer, the outer wall and the outer wall of the sunken road. The method for constructing the sunken road under the sandbar bridge provided by the embodiment adopts the inclined cement mixing pile method to improve the soil body, can stabilize the soil body and solve the defect of insufficient bearing capacity of the foundation, and can perform the soft foundation treatment construction of the sunken road under the conditions of insufficient construction clearance under the bridge and high underground water level.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a schematic plan view of a shoal bridge and a sunken road in the method for constructing a sunken road under the shoal bridge according to the embodiment of the present application;

fig. 2 is a schematic longitudinal sectional view of a modified soil layer treatment of a sunken road in the method for constructing a sunken road under a sandbar bridge according to the embodiment of the present application;

fig. 3 is a schematic cross-sectional view illustrating a modified soil layer treatment of a sunken road in the method for constructing a sunken road under a sandbar bridge according to the embodiment of the present disclosure.

In the figure: 100. a sandbar bridge; 110. inclining a cement mixing pile machine station line; 120. improving the soil layer; 130. a waterproof curtain wall; 140. an anti-floating anchor rod; 150. a water collecting and draining ditch; 160. a waterproof layer; 170. is near the water surface.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The characteristics and performance of the method for constructing a sunken road under a sandbar bridge according to the present invention will be described in further detail with reference to the following examples.

As shown in fig. 1, 2 and 3, an embodiment of the present application provides a method for constructing a sunken road under a sandbar bridge, including the following steps:

measuring a lofting road side line, a slope line excavated at two sides of a sunken road, an inclined cement mixing pile machine station line 110, a water-stop curtain line and point positions; the safety protection distance between the inclined cement mixing pile machine station line 110 and the bridge of the sandbank bridge 100 is 3m, and the inclined cement mixing pile machine station line 110 is located at an expansion joint of the sunken road structure;

on a sunny day in a dry season, a digger is used for digging a sunken road from two ends to the inclined cement mixing pile machine station line 110, slope putting is formed by construction on two sides of the sunken road, an underbridge soil body of the sandbank bridge 100 is reserved as a prepressing layer in advance, the distance between the prepressing layer, namely a digging finish surface of the sunken road and the bottom surface of a roadbed is 50cm, it is ensured that no underground open water is seen at the bottom of the finish surface of the inclined cement mixing pile machine station line 110, an operation surface in front of the inclined cement mixing pile machine station line 110 is ensured to have an operation surface of 2m, and a safe and stable side slope is formed by slope contraction of the soil body in front of the operation surface in front of the inclined cement mixing pile machine station line 110;

pile positions are seamlessly and densely distributed on an inclined cement mixing pile machine station line 110, so that all pile bodies are arranged in a tangent mode, construction is synchronously and symmetrically carried out from two sides of a bridge in operation, a horizontal center line of a lower penetration type road is used as a boundary, pile jumping construction is carried out from one side of a bridge of a sandbank bridge 100 to one side of a waterside surface 170, each pile position is firstly vertically constructed in construction, then, the pile positions are sequentially and horizontally stirred to form an improved soil layer 120, the construction interval time of the adjacent pile positions is below 8h, 4-step speed change is carried out according to the concentration change of a repeated rotating part when each pile position is subjected to rotary spraying construction, the cement mixing amount of the pile positions is 15% of the reinforced soil amount, the strength of the improved soil layer 120 is not less than C15, and each side edge of the improved soil layer 120 exceeds the outer wall of the subsidence type road in the width direction by more than 20 cm.

After the improved soil layer 120 is maintained for more than 7 days, excavating the soil body of a pre-pressed layer which is not excavated below the bridge, making slope protection or a short retaining wall on the side part of the abutment of the sandbank bridge 100 for stabilization, constructing the soil body inside the water-facing surface 170 to form an inclined water-stop curtain wall 130, wherein the water-stop curtain wall 130 is formed by double rows of water-stop curtain piles, the inclination angle of the water-stop curtain wall 130 is 45 degrees and is greater than the slope of the side slope, the minimum vertical distance between the wall body of the water-stop curtain wall 130 and the upward slope line of the river dike is more than 2m, and the minimum vertical distance is above the water level of the river;

after the improved soil layer 120 is maintained for more than 14 days, roadbed excavation of a sunken road is carried out, wheel type mechanical construction is adopted to excavate a road subbase layer, 2% of the base layer of the road subbase layer faces two sides to find slopes, then water collecting and draining ditches 150 are excavated along two sides of the improved soil layer 120, open drainage is adopted, water collecting wells are collected towards two sides of a bridge, a dewatering well is arranged at the bottom of each water collecting well, each water collecting well is a reinforced concrete structure square well, the length of the inner clear side is 1.5m, then anti-floating anchor rods 140 are constructed in the improved soil layer 120, firstly, impact drilling is carried out on the anti-floating anchor rods 140 in the improved soil layer 120, the anti-floating anchor rods 140 are arranged in a flower hole mode instead of a 'well' shape, the improved soil layer 120 is prevented from being broken, then the anti-floating anchor rods 140 are placed down by a method of welding and placing down in sections, and pressure grouting is adopted, and grouting pressure reaches 1.5 MPa.

The method comprises the steps of performing hair kicking and washing on a road subbase, using C15 cushion concrete for compensation and leveling to ensure that a base surface is level, smearing waterproof factice on the interface position of a reinforcing steel bar of the floating anchor rod 140 and the cushion, performing SBS waterproof asphalt waterproof coiled material construction after brushing the factice on the leveling layer of the road subbase to complete waterproof layer 160 construction, and then performing construction of a sunken road structure layer, namely performing ponding side ditch construction, expansion joint construction, road surface layer construction, outer wall waterproof construction and outer wall backfilling construction of the sunken road.

The sinking road construction method under the sandbar bridge provided by the embodiment aims at the conditions of insufficient clearance under the sandbar bridge, high ground water level and soft foundation, the inclined cement mixing pile machine is used for soil body improvement, soft and wet soil is integrally mixed and agglomerated to form an improved soil layer 120, the bearing capacity and the impermeability of the improved soil body are improved, thereby reducing the disturbance of the foundation, enhancing the implementation of the anti-floating anchor rods 140, avoiding the rolling of the road bed by a road roller, reducing the disturbance of the foundation caused by excavation and rolling vibration, reducing the influence of vibration on the foundation, greatly saving the cost and the complexity of the measure process, meanwhile, the inclined cement mixing pile machine is used for constructing the waterproof curtain, so that the large osmotic water pressure of the water surface 170 can be effectively reduced, the open discharge pressure is reduced, the occurrence probability of the osmotic pressure roof fall spring is reduced, the side slope can be solidified, and the corrosion of the slope bank wave and tide to the side slope after the soil body is improved and agglomerated and the sunk road structure is constructed is reduced. The construction method of the sunken road under the sandbar bridge provided by the embodiment is simple and smooth in process, improves construction efficiency, shortens construction period, saves construction cost, and is suitable for wide popularization and application.

The embodiments described above are some, but not all embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.