CN115262567A - An ultra-narrow full hard rock deep foundation pit excavation method - Google Patents

Abstract

An ultra-narrow full-hard rock deep foundation pit excavation method. On the plane, the excavation method is adopted from both ends to the middle, and the construction is divided into multiple construction sections according to the length of the foundation pit; vertically, with the depth of the excavation , Form platforms at different excavation depths of the excavation profile, and realize relay excavation and slag transportation through the cooperation of excavation machinery on different platforms. This method effectively utilizes the space effect. On the plane, the machine is reasonably arranged at different positions inside and outside the foundation pit. On the vertical direction, the steps are arranged, and the machine is reasonably arranged in different excavation layers. The rapid excavation effect of the grab bucket loading and slag removal effectively solves the construction problems of insufficient equipment working space under the ultra-narrow foundation pit width, and the small support spacing cannot be set up for conventional horse road slag removal.

Description

A method for excavating an ultra-narrow full-hard rock deep foundation pit

technical field

The invention belongs to the field of geotechnical engineering construction, and in particular relates to an ultra-narrow full-hard rock deep foundation pit excavation method.

Background technique

The foundation pit refers to the space below the ground excavated for the construction of the foundation and basement of buildings (including structures). A deep foundation pit refers to a project where the excavation depth exceeds 5 meters (including 5 meters), or the basement has more than three floors (including three floors), or the depth does not exceed 5 meters, but the geological conditions, surrounding environment and underground pipelines are particularly complicated. Hard rock refers to rocks whose particles are firmly connected and have high mechanical strength. Full hard rock refers to full-section hard rock, and the compressive strength of hard rock is greater than 60Mpa. Ultra-narrow means that the width of the foundation pit is less than or equal to 8 meters.

The invention patent application with the publication number CN109594564A discloses a construction method for open excavation and anti-collapse of a deep foundation pit. Dewatering around the foundation pit; S2: Rotary drilling and drilling piles, making enclosure piles; S3: Concrete support for crown beams; S4: Excavating soil for deep foundation pits, erecting steel supports; S5: Repairing slopes, soil nailing Drilling, placing soil nails, and grouting soil nails; S6: Repeat steps S4-S5 until the required depth of the foundation pit is reached. In steps S4 and S5, adopt vertical layering, horizontal block excavation, trench excavation, and soil retaining wall excavation, erect steel supports in time, and reduce the unsupported area and exposure time of the foundation pit. When constructing the foundation pit, first construct the horseway in the center of the foundation pit, dig the earthwork in the middle first, keep the side pressure soil on both sides of the foundation pit, and use the side pressure soil as the erection platform for the steel support. After the steel support is erected, continue to Excavation is repeated in this way until the foundation pit is dug to the designed depth.

Under ultra-narrow foundation pit operation conditions, conventional excavation equipment does not meet the requirements of the working space. At the same time, in the case of complex construction environments, the internal support system of the foundation pit is mostly designed with reinforcement and encryption. In the case of foundation pit construction, such a small support distance cannot be slag-discharged by setting a conventional horseway like the technical solution in the invention patent application of CN109594564A, so the construction risk, technical complexity and The difficulty of construction organization is much greater than that of conventional foundation pit engineering.

Therefore, there is an urgent need for a convenient and safe method for excavating ultra-narrow full hard rock deep foundation pits.

Contents of the invention

The technical problem to be solved by the present invention is that when the existing conventional foundation pit excavation method is used for ultra-narrow full hard rock deep foundation pit construction, the construction environment is complicated, and the conventional excavation equipment does not meet the requirements under the condition of narrow working width and small support spacing. The working space is required and it is impossible to set up conventional slag discharge.

In order to make up for the deficiencies of conventional excavation techniques and solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

An ultra-narrow all-hard rock foundation pit excavation method, on the plane, adopts the excavation method from both ends to the middle, and can be divided into multiple construction sections according to the length of the foundation pit; vertically, with the deepening of the excavation , platforms are formed at different excavation depths in the excavation profile, and through the cooperation of excavation machines on different platforms, relay excavation and slag transportation are realized.

With the above ultra-narrow all-hard rock foundation pit excavation method, the simultaneous construction of multiple construction sections speeds up the construction progress; at the same time, the cooperation of excavation machinery on platforms with different excavation depths, relay excavation and slag transportation speed up the excavation speed of the foundation pit and slag discharge speed.

According to the ultra-narrow full hard rock foundation pit excavation method of the present invention, it comprises the following steps:

Step S1, building enclosure structures such as enclosure piles, enclosure crown beams and retaining walls, and excavating the foundation pit after the enclosure structure strength meets the requirements;

Step S2, the excavation of the foundation pit is carried out from both ends to the middle, and the slope ratio is strictly controlled. Stonework machinery is arranged in different plane positions in the foundation pit and around the foundation pit, and the stonework machinery is used to complete the stonework excavation and transfer. The excavation progress of the foundation pit shall be carried out in time for the erection of the first steel support and slope support;

Step S3, as the excavation deepens, arrange the excavation machinery layer by layer at different excavation depths of the excavation profile, and use the excavation machinery to complete the excavation of the foundation pit; carry out the second excavation in time with the excavation progress of the foundation pit. Daogang support erection and slope support.

According to the method for excavating an ultra-narrow all-hard rock foundation pit of the present invention, the three-dimensional effect of machinery at different plane positions and different elevations is used during the excavation process to speed up the progress of foundation pit excavation and the efficiency of slag removal.

According to the ultra-narrow full hard rock foundation pit excavation method of the present invention, wherein, in step S2, the foundation pit excavation method is loose blasting with excavation machinery, and the excavation machinery includes stonework excavation machinery, and the The excavator completes the excavation of the foundation pit.

According to the ultra-narrow full hard rock foundation pit excavation method of the present invention, in step S2, the different plane positions include the range of the foundation pit and the two sides outside the range of the foundation pit, and the stonework machinery includes an excavator, a breaker, a vertical grab Bucket machine, stone transport vehicle.

According to the method for excavating an ultra-narrow full hard rock foundation pit of the present invention, the steel supports in steps S2 and S3 are Φ609 steel supports, and the slope support includes bolt support and shotcrete support.

According to the method for excavating an ultra-narrow full hard rock foundation pit of the present invention, platforms of different elevations are formed on the excavation section. Includes a top platform near the top of the pit and a bottom platform near the bottom of the pit.

Use the stonework machinery arranged on the top platform to cooperate with the stonework machinery on the bottom platform to transfer the stonework in the bottom platform to the top platform, and use the vertical transport machinery to lift the stonework in the top platform to the outside of the foundation pit , using the stonework machinery to transport the stonework to the designated area.

The stonework machinery at the bottom platform is used to excavate the stonework at the bottom of the foundation pit and cooperate with the stonework machinery on the top platform to transfer the stonework at the bottom of the foundation pit to the top platform.

When the number of platforms formed by different excavation depths is greater than or equal to 3, it also includes an intermediate platform whose elevation is located between the top platform and the bottom platform, and the intermediate platform can be one or a plurality of intermediate platforms with different elevations; The stonework machinery on the upper platform transfers the stonework on the bottom platform to the top platform.

The stonework machines arranged on the top platform, bottom platform and middle platform include excavators and breaking hammers.

According to the method for excavating an ultra-narrow full hard rock foundation pit of the present invention, the vertical transportation machine is a vertical grab machine, and the stonework machinery includes: an excavator and a stonework transport vehicle.

According to the excavation method of the ultra-narrow full hard rock deep foundation pit of the present invention, the space effect is effectively utilized, the machinery is reasonably arranged at different positions inside and outside the foundation pit on the plane, steps are arranged vertically, and the machinery is reasonably arranged at different excavation layers to realize multiple excavations. The rapid excavation effect of table excavator relay excavation, slag transportation, and grab bucket loading and slag discharge in the middle of the foundation pit effectively solves the problem of insufficient working space for equipment under ultra-narrow foundation pit width parts and the inability to set up conventional horseway slag discharge with small support distances construction problems.

Description of drawings

Fig. 1 is the process flow chart of ultra-narrow full hard rock deep foundation pit excavation construction method according to the present invention;

Fig. 2 is the plane distribution diagram of working conditions of the ultra-narrow full hard rock deep foundation pit excavation construction method according to the present invention;

Fig. 3 is a working condition longitudinal schematic diagram of a preferred scheme of the ultra-narrow full hard rock deep foundation pit excavation construction method according to the present invention;

Fig. 4 is a schematic plan view of working conditions of a preferred solution of the ultra-narrow full hard rock deep foundation pit excavation construction method according to the present invention.

in,

1 - the first excavator;

2 - the second excavator;

3 - the third excavator;

4 - the fourth excavator;

5 - the fifth excavator;

6 - the sixth excavator;

7——The first stone cube transport vehicle;

8——the second stone transport vehicle;

9——Vertical lifting grab machine;

10——steel support;

11—the activity area of the first excavator;

12 - the second excavator activity area;

13—the third excavator activity area;

14—the fourth excavator activity area;

15—the fifth excavator activity area;

16—the activity area of the sixth excavator.

Detailed ways

The present invention will be further described in detail below in conjunction with accompanying drawings 1-4 and specific embodiments.

An ultra-narrow all-hard rock foundation pit excavation method adopts the excavation method from both ends to the middle on the plane, as shown in Figure 2, and the direction indicated by the arrow is the excavation direction. According to the length of the foundation pit, it can be divided into multiple construction sections for simultaneous construction. As shown in Figures 3 and 4, vertically, with the deepening of the excavation, platforms are formed at different excavation depths of the excavation section, and through the cooperation of excavation machines on different platforms, relay excavation and slag transportation are realized.

As shown in Figure 1, the ultra-narrow all-hard rock deep foundation pit excavation construction method mainly includes the following steps:

Step S1: Build enclosure structures such as enclosure piles, enclosure crown beams, and retaining walls, and excavate the foundation pit after the enclosure structure strength meets the requirements;

Step S2: The excavation of the foundation pit is carried out from both ends to the middle, and the slope ratio is strictly controlled. Stonework machinery is arranged in different plane positions in the foundation pit and around the foundation pit, and the stonework machinery is used to complete the stonework excavation and transfer. The excavation progress shall be carried out in time for the erection of the first steel support and slope support;

Step S3: As the excavation deepens, the excavation machines are arranged layer by layer at different excavation depths of the excavation profile, and the excavation machines are used to complete the excavation of the foundation pit. With the excavation progress of the foundation pit, the second steel support erection and slope support shall be carried out in time.

In step S2, on the plane, as shown in Fig. 2, the excavation method is adopted from both ends to the middle, and the excavation speed can be accelerated by dividing the excavation into multiple construction sections according to the length of the foundation pit. During the excavation of the foundation pit, due to the ultra-narrow width of the foundation pit and the small spacing between supports, only one excavation equipment can be accommodated in the same section, and the excavation machine cannot turn around normally to change the excavation direction by turning, and cannot be set up in a conventional way The road is slag. In this case, the above-mentioned excavation method in the plane is based on rationally arranging the number and location of excavation machines, and specifying the excavation direction in advance when the machines enter the foundation pit. Excavation machinery cooperates to realize relay slag discharge and improve excavation efficiency.

In step S3 of the foundation pit excavation process, rockwork machinery is reasonably installed at different plane positions, and the stonework excavation and transfer are completed by using the machinery. During the excavation process, the three-dimensional effect of the machine in different plane positions and different elevations is fully utilized to speed up the excavation progress of the foundation pit and the efficiency of slag discharge.

In step S3, vertically, as the excavation deepens, platforms are formed at different excavation depths of the excavation profile for the arrangement of these stonework machines. When excavating, the excavator or breaker located on the upper floor excavates the steps of this layer and the lower layer within the excavation range. After the lower steps are completed, the steps are used as a platform to arrange the excavator or breaker. During the excavation process Use the excavators on the upper and lower platforms to carry out relay transfer of crushed gravel, and use vertical transport machinery to lift the concentrated piled crushed gravel on the upper platform to the outside of the foundation pit, and use stonework machinery to transport the stonework to the designated area. Excavate circularly to the bottom of the foundation pit according to this method. After the excavation of the foundation pit is completed, use the vertical lifting machine to lift the stone excavation machine in the foundation pit to the outside of the foundation pit.

Step S3 is described by taking FIG. 3 as an example. At the beginning of construction, 4 excavators are arranged, and the excavators are the first excavator 1, the second excavator 2, the third excavator 3, and the fourth excavator 4, wherein the first excavator 1, the third excavator 3 Excavate the stonework within the range of the top platform near the top of the foundation pit in a forward manner, and the second excavator 2 and the fourth excavator 4 transfer the stonework dregs on both sides of the foundation pit and cooperate with the first stonework transportation Vehicle 7 and the second stone transport vehicle 8 transfer the muck; in the second construction stage, when the lower steps are formed during excavation, the first excavator 1 and the third excavator 3 enter the middle platform to excavate the next layer in a forward manner Stonework, after the excavation of the first and third excavator activity areas 11 and 13 is completed, the first and third excavator machines 1 and 3 stay in the first and third excavator activity areas 11 and 13 to unload the stone The second excavator 2 and the fourth excavator 4 enter the top platform near the top of the foundation pit from the outside of the foundation pit, and excavate in a backward manner close to the foundation pit For the stonework on the bottom platform at the bottom, the first excavator 1 and the third excavator 3 cooperate with the second excavator 2 and the fourth excavator 4 to transfer the stonework in the bottom platform to the top platform. The fifth excavator 5 and the sixth excavator 6 are arranged on the top, and the excavators all adopt the reverse mode to excavate the stonework in the fifth and sixth excavator activity areas 15 and 16 of the top platform range on the top of the foundation pit. Utilize the vertical transport machinery to vertically lift the grab machine 9 to lift the stone in the top platform to the outside of the foundation pit; in the third construction stage, after the excavation of the top platform near the top of the foundation pit is completed, all excavators enter the interior of the foundation pit, Use the above excavation steps to excavate the remaining foundation pit stonework in a cycle. During the excavation process, the direction of travel of all excavators does not change, and use the vertical transport mechanism to vertically lift the grab machine 9 to lift the stonework produced by the excavation to the foundation pit. Externally, after all stone excavation is completed, the excavator is lifted to the outside of the foundation pit by vertical transport machinery.

The forward excavation refers to excavation from both ends of the foundation pit to the middle of the foundation pit; the backward excavation refers to excavation from the middle of the foundation pit to both ends of the foundation pit.

Step S4 is described by taking FIG. 4 as an example. Fig. 4 is a schematic diagram of the position change of the stonework machine plane in step S3, corresponding to the construction start stage, the second construction stage, and the third construction stage respectively, wherein the first and third excavators 1 and 3 are arranged inside the foundation pit in the start construction stage, and The second and fourth excavators 2 and 4 and the first and second stonework transport vehicles 7 and 8 are arranged outside the foundation pit, and the first and third excavators 1 and 3 carry out stonework within the range of the top platform near the top of the foundation pit Excavation, the second and fourth excavators 2 and 4 transfer the excavated stonework and cooperate with the first and second stonework transport vehicles 7 and 8 to transfer the stonework to the designated location; in the second construction stage, add layout The fifth and sixth excavators 5, 6, and vertical lifting grabs 9, all excavators are arranged on top platforms, bottom platforms, and intermediate platforms of different elevations formed by excavation, and vertical lifting grabs 9 are arranged on the base platform. Outside the pit, vertically lift the excavated stonework to the outside of the foundation pit; the plane layout of the stonework excavation machinery in the third construction stage is the same as that in the second construction stage.

During the excavation of the foundation pit, complete the foundation pit support construction in time according to the excavation progress to ensure the safety of the foundation pit excavation construction. In step S3, the steel support 10 is a Φ609 steel support, and the slope support includes bolt support and shotcrete support.

The above ultra-narrow full hard rock deep foundation pit excavation method effectively utilizes the space effect, rationally arranges machinery at different positions inside and outside the foundation pit on the plane, sets steps vertically, and reasonably arranges machinery at different excavation layers, so that multiple excavations can be realized. The rapid excavation effect of mechanical relay excavation, slag transportation, and slag loading by grab bucket in the middle of the foundation pit effectively solves the problem of insufficient equipment working space under the ultra-narrow foundation pit width, and the construction of conventional horse road slag discharge that cannot be set at a small support distance problem.

The above content is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Various modifications and variations of the present invention will occur to those skilled in the art. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims (9)

1. The ultra-narrow full-hard rock deep foundation pit excavation construction method is characterized by comprising the following steps of:

on a plane, an excavation mode from two ends to the middle is adopted, and construction is divided into a plurality of construction sections according to the length of a foundation pit;

and in the vertical direction, along with the deep excavation, platforms are formed at different excavation depths of the excavation section, and the relay excavation and slag conveying are realized through the cooperation of excavation machines on different platforms.

2. The ultra-narrow all-hard rock deep foundation pit excavation construction method according to claim 1, characterized by comprising the following steps:

s1, constructing a fender pile, a fender crown beam and a retaining wall fender structure, and excavating a foundation pit after the strength of the fender structure meets the requirement;

s2, excavating the foundation pit from two ends to the middle, strictly controlling the slope ratio, arranging stone machines in the foundation pit and at different plane positions on the periphery of the foundation pit, finishing stone excavation and transportation by using the stone machines, and timely erecting a first steel support and supporting a side slope along with the excavation progress of the foundation pit;

s3, arranging excavation machinery layer by layer at different excavation depths of an excavation section along with the excavation depth, and completing excavation of a foundation pit by using the excavation machinery; and (5) erecting a second steel support and supporting a side slope in time along with the excavation progress of the foundation pit.

3. The ultra-narrow all-hard rock deep foundation pit excavation construction method according to claim 2, characterized in that:

the foundation pit excavation mode in the step S2 is loose blasting cooperation excavation machinery, the excavation machinery comprises stone excavation machinery, and excavation of the foundation pit is completed through the excavation machinery.

4. The ultra-narrow all-hard rock deep foundation pit excavation construction method according to claim 2, characterized in that:

the different plane positions in the step S2 comprise two sides in the range of the foundation pit and outside the range of the foundation pit;

the stone square machine comprises an excavator, a breaking hammer, a vertical grab bucket machine and a stone square transport vehicle.

5. The ultra-narrow all-hard rock deep foundation pit excavation construction method according to claim 2, characterized in that:

the steel support in the step S2 and the step S3 is a phi 609 steel support;

the side slope support comprises anchor bolt support and sprayed concrete support.

6. The ultra-narrow all-hard rock deep foundation pit excavation construction method according to claim 1, characterized in that:

the platforms formed by different excavation depths comprise a top platform close to the top of the foundation pit and a bottom platform close to the bottom of the foundation pit;

the method comprises the following steps that a stone machine arranged on a top platform is matched with a stone machine on a bottom platform to transfer stones in the bottom platform to the top platform, a vertical conveying machine is used for lifting the stones in the top platform to the outside of a foundation pit, and the stone machine is used for conveying the stones to a designated area;

and excavating the stone below the foundation pit by using the stone machinery arranged on the bottom platform and transferring the stone below the foundation pit to the top platform by matching with the stone machinery on the top platform.

7. The ultra-narrow all-hard rock deep foundation pit excavation construction method according to claim 6, characterized in that:

the platform is formed at different excavation depths and also comprises a middle platform with the elevation between the top platform and the bottom platform, and the middle platform can be one or a plurality of middle platforms with different elevations;

the stones on the bottom platform are transferred to the top platform by means of stone machines arranged on the intermediate platform.

8. The ultra-narrow all-hard rock deep foundation pit excavation construction method according to claim 7, characterized in that:

the stone square machines arranged on the top platform, the bottom platform and the middle platform comprise excavators and breaking hammers.

9. The ultra-narrow all-hard rock deep foundation pit excavation construction method according to claim 6, characterized in that:

the vertical transport machinery is a vertical grab bucket machine;

the stone square machine includes: excavator, stone side transport vechicle.

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