CN113091541A

CN113091541A - Low-vibration blasting diaphragm wall demolition construction method

Info

Publication number: CN113091541A
Application number: CN202110397548.4A
Authority: CN
Inventors: 王睿; 任鹏鹏; 周翔; 申长剑; 李建明; 刘晓欢
Original assignee: China Railway Sixth Group Co Ltd; Taiyuan Railway Construction Co Ltd of China Railway Sixth Group Co Ltd
Current assignee: China Railway Sixth Group Co Ltd; Taiyuan Railway Construction Co Ltd of China Railway Sixth Group Co Ltd
Priority date: 2021-04-14
Filing date: 2021-04-14
Publication date: 2021-07-09
Anticipated expiration: 2041-04-14
Also published as: CN113091541B

Abstract

The invention relates to subway construction, in particular to a construction method for demolishing a diaphragm wall by low-vibration blasting; the method comprises the following steps: (1) designing a blasting scheme and preparing construction; (2) building a working platform; (3) drilling, cleaning and checking holes; (4) filling the explosive after the explosive is manufactured, and performing blocking work after the explosive is filled; (5) laying a blasting network, connecting a detonating tube detonating network, checking the detonating network, and performing safety protection and warning; (6) detonating after warning, and checking a blind gun after blasting; (7) digging soil outside the underground diaphragm wall, cutting the steel bars and removing slag; the method has high construction efficiency and short construction period, compared with the conventional method, the blasting work can be completed before the excavation of the earthwork at the outer side of the diaphragm wall, only slag and cutting reinforcing steel bars need to be processed in the excavation process, the concrete crushing time is saved, and the construction period is shortened to a great extent; the vibration is controllable, and the safety and the reliability are realized; the overall cost is low, and the steel bars in the wall body are easy to recover.

Description

Low-vibration blasting diaphragm wall demolition construction method

Technical Field

The invention relates to subway construction, in particular to a low-vibration blasting diaphragm wall demolition construction method.

Background

In the construction of a subway station, in order to ensure that the construction site is often limited due to temporary traffic, a station main body and an attached structure are often constructed in stages, and when the two-stage structure main body is connected, a temporary enclosure structure during the previous stage of structure construction needs to be dismantled. The diaphragm wall is used as a common enclosure structure of a subway station, has the characteristics of high rigidity and good integrity, but the characteristic also causes the difficulty in dismantling the diaphragm wall, high cost and long time consumption. The construction method for dismantling the diaphragm wall usually adopts a manual work and a mechanical work to dismantle reinforced concrete or uses a rope saw to cut, wherein the former has the defects of long time consumption and large vibration, and the latter has the defect of high manufacturing cost.

Disclosure of Invention

The invention overcomes the defects of the prior art, provides a construction method for demolishing the diaphragm wall by low-vibration blasting, combines the actual construction condition and the construction characteristics of smooth blasting, and provides a construction method for demolishing the underground diaphragm wall by low-vibration protective blasting.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: 1. a low-vibration blasting diaphragm wall demolition construction method is characterized by comprising the following steps:

(1) designing a blasting scheme and preparing construction, wherein arrangement modes and number of main blast holes, cut holes, buffer blast holes and light blasting blast holes are respectively designed, the horizontal wedge-shaped cut holes are arranged in the middle of a crushing blasting wall body, a row of light blasting or presplitting holes are drilled in the protective blasting wall body, and a row of buffer holes are drilled between the crushing blasting wall body and the protective blasting wall body; the blasting adopts a sectional millisecond detonating tube, the blasting sequence is from top to bottom, namely from one layer to two layers, the middle cut → the main blast hole → the buffer hole → the light blast hole is divided into sections and blocks by adopting the principle of 'more holes and less powder charge';

(2) building a working platform, drilling and charging by using a lifting trolley, and building a drilling and charging working platform by using a scaffold for individual section buildings;

(3) drilling, cleaning and checking holes;

(4) (4) preparing water-resistant emulsion explosive, a detonator, a detonating tube and a lead, making a detonating body, charging, and performing plugging work after charging;

(5) laying a blasting network, connecting a detonating tube detonating network, checking the detonating network, and performing safety protection and warning;

(6) detonating after warning, and checking a blind gun after blasting;

(7) digging soil outside the underground diaphragm wall, cutting the steel bars and removing slag.

Further, in the step (1), on the premise that the hole depth L & gt W is ensured, the bottom of the wall has no empty surface, and L & gt (0.7-0.8) H is taken, wherein L is the hole depth, W is the minimum resistant line, and H is the thickness of the wall to be removed; a continuous or layered charge structure is adopted; a compound initiation mode of a non-electric detonator and an electric detonator is adopted, and a multi-loop compound network is adopted, namely, a explosive packet is initiated by an initiation detonator, and the initiation detonator adopts a group parallel network and is initiated by the electric detonator; through blasting safety design, calculation guarantees that blasting vibrations can not cause the influence to the protection target, simultaneously through calculating flying stone safe distance, takes the parcel to cover, makes flying stone control in effective range.

And (3) further, the drilling in the step (3) is horizontal drilling, the holes are inspected to check whether the distance, the row spacing and the hole depth of the blast holes meet the design requirements, whether sundries exist in the blast holes or not is checked, the blast holes are cleaned in time after the sundries are found, all the blast holes are marked, and the number, the detonator section and the explosive loading of each hole are noted.

Further, the filler selected for plugging after the powder charging in the step (4) is loess, stemming plugging is made, the stemming is tamped by a stick, and the stemming is filled until the hole opening is level.

Compared with the prior art, the invention has the following beneficial effects:

1. the construction efficiency is high, and the time limit for a project is short, and for conventional way, blasting work can be accomplished before the excavation of the earth outside the diaphragm wall, only need handle the disintegrating slag and cut the reinforcing bar among the excavation process, has removed concrete crushing time from to constructor's special strong, efficient to constructor's input time has been reduced, does not have the construction intermittence, and to a great extent has shortened the time limit for a project.

The blasting design is carried out in a partitioning and blocking mode by adopting the principle of 'multiple holes distribution and less explosive loading', the calculation of vibration and flying stones is included in the design calculation, the influence of construction on the surrounding environment is reduced to the minimum and the vibration is in a reasonable range through theoretical calculation, and compared with a mechanical dismantling scheme of a crushing gun, the vibration can be controlled through a hole distribution mode and the explosive loading amount.

3. The overall cost is low, the steel bars in the wall body are easy to recover, the comprehensive single price of the blasting method is lower than that of the traditional method, and the blasting method can separate the steel bars in the underground diaphragm wall from the concrete, so that compared with the traditional method, the blasting method can recover the steel bars in the underground diaphragm wall, and further reduce the overall cost.

Drawings

Figure 1 is a schematic of the continuous charge configuration of example 1.

Figure 2 is a schematic diagram of the layered charge of example 1.

Fig. 3 is a schematic view of the demolition scheme of the blasting of the underground diaphragm wall in example 1.

Fig. 4 is a layout view of the demolition blastholes of the wall-connected blasting in example 1.

Fig. 5 is a schematic diagram of a detonator network of example 1.

The figures are labeled as follows:

1-blocking part, 2-explosive, 3-millisecond detonating tube and 4-concrete.

Detailed Description

The present invention is further illustrated by the following specific examples.

Example 1

In this embodiment, the method for constructing and dismantling the underground diaphragm wall by low-vibration blasting is adopted by taking the example that the original urban rail transit line 2 and line 3 are constructed simultaneously to dismantle the underground diaphragm wall at the T-shaped transfer station jin Yang street station.

The jin yang street station is a T-shaped transfer station constructed by a 2 # line and a 3 # line of the Taiyuan urban rail transit at the same time and is positioned at the intersection of the Changzhi road and the jin yang street, the 2 # line station is arranged along the south-north direction of the Changzhi road, and the 3 # line is arranged along the east-west direction of the jin yang street at the east side of the intersection. The length of the transfer node between the No. 2 line and the No. 3 line is 28.6m, the width of the transfer node is 23.1m, the main structure is of a three-layer structure, the depth of a foundation pit is 27.9m, the thickness of top plate soil covering is 5.5m, when the first layer and the second layer of the transfer node are connected with the south portion and the north portion of the No. 2 line which are constructed, a ground connecting wall of an original construction enclosure structure needs to be removed, the thickness of the ground connecting wall is 0.8m, the height of the ground connecting wall needs to be 13.54m on the south side and 14.89m on the north side, the width of the foundation pit needs to be 23.1m, and the square amount of reinforced concrete. The continuous wall with the thickness of 800mm is thick and dense in reinforcement, wherein the main reinforcement is phi 32@240mm, and the continuous wall also comprises a plurality of constructional reinforcements such as tie bars, oblique reinforcements and the like, and the concrete has a high grade and the strength of C35.

The surrounding environment of the explosion area:

the blasting point is below 5 meters underground, is positioned at the intersection of the long road and the Jinyang street and is 20-25 meters away from the ground building.

In order to reduce the influence on the structure and the periphery, a feasible dismantling construction scheme must be selected. Through a common reinforced concrete demolition construction process, a blasting method of subsection differential time delay in a subarea (from a negative layer to a negative layer) is finally selected for demolition according to the sequence of a middle undermining, a main blasting hole, a buffer hole and a light blasting hole.

Firstly, designing blasting scheme and preparing construction

(1) The row spacing, the hole depth and the blast hole direction are very important for ensuring the blasting effect. Adopting a horizontal blast hole, ensuring that the L & gt is W, ensuring that no blank surface exists at the bottom, and taking L as (0.7-0.8) H, wherein L is the hole depth, W is the minimum resistant line, and H is the thickness of a wall to be dismantled; the unit consumption of explosive is determined by various factors such as concrete strength, section reinforcing condition, the number of free faces, the environment of an explosion area, the crushing degree, the type of blast holes and the like.

Table 1 blasting design parameter table

TABLE 2 blasting parameter table for conjoined wall

(2) Arrangement diagram of blast holes

According to the characteristics of the exploded structure, a continuous double-layer (layered) charging structure is adopted for reasonably distributing explosive energy. The charge configuration is shown in figures 1 and 2. The burst demolition scheme for the diaphragm wall is shown in fig. 3. The arrangement of the blasting demolition blastholes of the underground continuous wall is shown in figure 4.

(3) Detonation mode and detonation network

The feature of the blasting structure determines the arrangement and dispersion of the blasting holes, the number of the blasting holes is large, in order to ensure accurate blasting, a non-electric detonator and electric detonator compound blasting mode is adopted, and a multi-loop composite network is adopted, namely, a explosive package is blasted by a blasting detonator, and a detonating tube is detonated by an electric detonator by a group parallel network. The detonator network is shown in figure 4,

(4) safety design of blasting

And (3) vibration calculation:

V＝k(Q^1/3/R)^α＝250(5^1/3/20)²＝250×0.0073＝1.8cm/s﹤V_an3.0 cm/s. The blasting vibration does not affect the protection target.

Checking and calculating the safety distance of the flying stones:

L_{fly away}70 × K × 0.58, 70 × 0.7 × 0.58, 70 × 0.813, 56.91 m. The flyrock can be controlled within an effective range after being covered by the adopted package.

(5) Before blasting construction, a project department establishes a work group, a cooperative owner, a supervision and other related units to investigate on the spot, and makes a targeted protective measure to blame for people; setting up a warning area and making peripheral notification work.

And secondly, drilling and charging by using a lifting trolley, and building a drilling and charging working platform by using scaffolds for individual section buildings.

Thirdly, drilling, cleaning and checking the hole;

drilling holes

and a, blasting by adopting a horizontal drilling method, wherein the drilling depth is 0.6 m, and the aperture D is 48 mm.

b, drilling is strictly positioned according to the designed pitch, and the pitch positioning error is less than or equal to 20mm.

c, gradually applying force during drilling, and slowly pushing to prevent drill jamming. And the requirement is that the hole opening is complete and the hole wall is smooth, thereby facilitating slag discharge and later-stage charging.

d, drilling holes in sequence from one end according to the marked hole positions to prevent leakage.

e, after drilling holes with the depth of about 0.5-1.0cm, adjusting the position of the drilling machine in time to ensure the correct direction of the drilling holes.

f, after drilling holes in each area, checking whether holes are leaked or not, and timely drilling supplement after finding.

Hole inspection

a, checking whether the drilling operation is finished at all the positions required by the design.

And b, checking whether the distance, the row spacing and the hole depth of the blast holes meet the design requirements.

c, checking whether sundries exist in the blast holes or not, and timely cleaning after finding.

And d, marking all blast holes, and indicating the number of the blast holes, the section of the detonator and the explosive loading of each hole.

Fourthly, charging the explosive after the explosive is manufactured, and carrying out blocking work after the explosive is charged;

(1) charging operation

Moisture and water proofing of explosives

The explosive selected for blasting is water-resistant emulsion explosive.

Preparation of blasting materials and apparatus

Testing of detonation equipment

Adopting a random spot check method to carry out series and parallel quasi-explosion tests;

and simulating a detonation network for testing, and measuring the delay second quantity of the detonator.

Processing of pharmaceutical packs

And respectively determining the cutting length of each medicine package according to the weight of the medicine roll with unit length and the medicine loading amount of each medicine package, dividing the medicine according to the cutting length of each medicine package by using a ruler and a knife, and storing the medicine separately. When in use, the corresponding non-electric millisecond delay detonator is inserted.

Construction of filling medicine

In order to ensure the charge amount and the charge structure required by design, the explosive charge should be as follows:

firstly, each blasting part should be hung with a brand before charging, and the number of the detonator section and the explosive charging quantity are written on the brand.

Secondly, the explosive charging teams and groups are definitely divided into groups, the explosive charging personnel and the explosive transporting personnel are fixed by adopting a method of specified number matching explosive charging, and the explosive charging personnel is responsible for recording the explosive charging amount.

Thirdly, the medicine bag can not be damaged, if damaged, the medicine bag can be immediately replaced, and the medicine bag is moved lightly.

(2) Stuffing operations

In order to fully utilize the explosion energy of the explosive and prevent high-temperature and high-pressure explosive gas generated during explosion of the explosive from escaping along a blast hole, the explosive must be blocked according to design after charging. Requirements for plugging work:

a, preparing filling materials (loess) and paying attention to the moisture retention of the filling materials.

And b, tamping the stemming by using a wooden stick, strictly forbidding the occurrence of a cavity or an unrealistic phenomenon, and strictly forbidding putting the stemming into the stemming without tamping.

And c, filling the stemming until the hole opening is flush.

d, protecting the detonator leg wire or the detonating tube, and not tamping the gun stick on the detonator leg wire or the detonating tube.

e, ensuring the blocking length, and not allowing blasting if no plugged blast hole exists;

f, the plugging work needs to be carried out by a specially-assigned person in strict sequence, so that the plugging quality is ensured.

Laying a blasting network, connecting a detonating tube detonating network, checking the detonating network, and performing safety protection and warning;

(1) network laying

When connecting the detonating tube detonating circuit, the following technical points should be noted:

the detonating tube network should be connected strictly according to the design, there should be no dead knot in the detonating tube network, there should be no joint in the blast hole, and there should be enough distance between adjacent detonating detonators outside the hole.

Secondly, corresponding sections of detonators are bound according to the detonating sequence of the blast holes, and a special person checks the detonators to prevent binding by mistake or in disorder.

Thirdly, bundling the outgoing line of the detonating tube by using an adhesive tape, bundling the millisecond electric detonator after the detection is correct, and paying attention to the direction of the cumulative hole of the electric detonator opposite to the detonating tube explosion propagation direction during the bundling so as to prevent the electric detonator explosion copper sheet from cutting off the detonating tube to cause the misfire. The distance between the detonator of the detonating and detonating tube and the end of the bundling end of the detonating and detonating tube is not less than 15 cm.

And fourthly, before the network connection of the electric detonator, removing all the field equipment and irrelevant personnel in the explosion area, setting a warning, wherein the irrelevant personnel can not enter the explosion area uniformly, and connecting the network main outgoing line on the premise of ensuring the safety.

And fifthly, adopting a series-parallel composite network as the network, using colloid copper wires as the regional lines, wrapping joints with insulating tapes, and carrying out conduction and resistance tests.

After the network is connected, all lines are checked by a specially-assigned person, and the network end is treated by adopting an open circuit insulation measure so as to prevent the influence of stray electricity.

And (3) detonating network inspection:

the detonating network inspection should be performed by an inspection group consisting of experienced blasting workers, and the number of the inspection group is not less than two.

Secondly, the inspection content of the detonating tube detonating network comprises the following steps: whether the connection is missed or interrupted or broken; whether knotting or looping is performed or not; whether the detonator bundling meets the requirements; whether the line connection mode is correct or not and whether the number of detonator sections is consistent with the design or not; whether the network protection measures are reliable.

A detonation station:

carrying out negative one-layer blasting and negative two-layer blasting, wherein a blasting initiation station is arranged in a ground enclosure area; the horizontal distance is 150 meters. So as to prevent the blast wave and the blast fume from causing damage to the blasting constructors. And the detonating station is communicated with the conductor by adopting an interphone.

Sixthly, detonating after warning, and checking a blind shot after blasting;

the blasting warning range is organized according to the 200m range of blasting safety regulation, all indoor and outdoor personnel and staff in the warning line during blasting must be cleared, the personnel are evacuated to a safe place outside the safety warning line, no dead angle is left, the outlet is sealed, and meanwhile, a sound signal is given to ensure the blasting safety.

And (4) according to the design, defining a personnel warning ring, setting a sentry and a roadblock in a construction area before detonation, and forbidding irrelevant personnel from entering the construction area.

The warning personnel wear the red armband, the sentry holds the red flag and is provided with the warning board.

Under the unified coordination of the blasting command department, constructors and equipment are organically withdrawn to a safe area. Evacuation is started half an hour before the detonation, and evacuation must be finished before the first advance notice signal is sent.

The warning distance is as follows: the starting point is 100m outside the enclosing wall of the structure to be exploded.

The blasting process is strictly executed according to blasting safety regulations and related national laws and regulations.

And seventhly, digging soil on the outer side of the underground diaphragm wall, cutting the reinforcing steel bars and removing slag.

Claims

1. A low-vibration blasting diaphragm wall demolition construction method is characterized by comprising the following steps:

(3) drilling, cleaning and checking holes;

(4) preparing water-resistant emulsion explosive, a detonator, a detonating tube and a lead, making a detonating body, charging, and performing plugging work after charging;

(5) laying a blasting network, connecting a detonating tube detonating network, checking the detonating network, and setting safety protection and warning;

(6) detonating after warning, and checking a blind gun after blasting;

2. The construction method for demolishing the diaphragm wall through low vibration blasting according to claim 1, wherein in the step (1), on the premise of ensuring L > W, the bottom has no empty face, and L = (0.7-0.8) H is taken, wherein L is the hole depth, W is the minimum resistant line, and H is the thickness of the wall to be demolished; a continuous or layered charge structure is adopted; a compound initiation mode of a non-electric detonator and an electric detonator is adopted, and a multi-loop compound network is adopted, namely, a explosive packet is initiated by an initiation detonator, and the initiation detonator adopts a group parallel network and is initiated by the electric detonator; through blasting safety design, calculation guarantees that blasting vibrations can not cause the influence to the protection target, simultaneously through calculating flying stone safe distance, takes the parcel to cover, makes flying stone control in effective range.

3. The method for constructing the underground diaphragm wall through low-vibration blasting demolition is characterized in that horizontal drilling is adopted for drilling in the step (3), the distance, the row spacing and the hole depth of blast holes are checked to determine whether the distance, the row spacing and the hole depth meet the design requirements or not, whether sundries exist in the blast holes or not is checked, the blast holes are timely cleaned after finding, all the blast holes are marked, and the number of the blast holes, the detonator section and the explosive loading of each hole are noted.

4. The low-vibration blasting demolition ground wall construction method according to claim 1, wherein the filling material selected for plugging after the charging in step (4) is loess, stemming plugging is made, the stemming is tamped by a wooden stick, the stemming is filled until the orifice is flush, and the length of the orifice plugging is greater than the minimum resistance line.