CN108612546B - Horizontal grouting construction method in closed environment - Google Patents

Abstract

The invention discloses a horizontal grouting construction method in a closed environment, grouting is carried out on the front surface of a tunnel, and the grouting is carried out at the time of each circulation by 50m and is lapped by 10 m; and 76 grouting holes are arranged in the first cycle, wherein the depth of the holes B1-B9 is 15 meters, the depth of the holes A1-A67 is 50 meters, the diffusion radius is 1.3m, the length of the drain hole is 40m, the grouting holes are arranged at the bottom, and a flowmeter is arranged at the drain outlet to count the water discharge. The construction method for horizontal grouting in the closed environment is simple and convenient and has strong operability. The invention provides the double control of grouting pressure and grouting quantity, and the deformation of the closed body and the stratum can be effectively controlled by adopting the principle of double control and slow speed in the construction process. According to the invention, the grouting sequence is that the outer side is injected first and then the center, and the outer side is injected first, so that the influence of the grouting on the closed body is reduced. The invention focuses on information-based construction, and the monitoring condition guides the adjustment of parameters such as grouting pressure, grouting speed, grouting amount and the like. The invention can horizontally reinforce soil mass 50m at one time, which is beneficial to rapid centralized construction. The construction method of horizontal grouting in the closed environment is safe, reliable, efficient, economical and practical.

Description

Horizontal grouting construction method in closed environment

Technical Field

The invention relates to a horizontal grouting construction method in a closed environment, in particular to a horizontal grouting construction method in an enclosure wall environment formed by frozen soil.

Background

The tunnel or the section with the upper covering layer less than the tunnel hole by 2 times belongs to a shallow buried tunnel, and the shallow buried tunnel is more and more along with the development of social economy at present. Most of shallow-buried underground excavation tunnels are pre-supported in advance, and the pre-support comprises an advanced anchor rod, an advanced pipe shed, an advanced freezing support and the like. The cross section of the tunnel port underground excavation section in the north arch is 21m in height, 18.8m in width, 255m in length and 4-5 m in buried depth. The tunnel is located in a near-sea saturated soft soil environment, the geological condition is complex, the ground layers from top to bottom sequentially comprise artificial miscellaneous fill, silt, mucky soil, coarse (gravel) sand, sand (gravel) cohesive soil and residual soil, the underground water level is 3m high, and rich water is communicated with seawater. The curtain advance support and horizontal freezing water stop combined enclosure structure is adopted, and the thickness of a freezing wall is 2-2.6 m. The periphery of the section of the tunnel is a freezing ring, and the interior of the section of the tunnel is rich-water soft soil, so that the stability of excavation can be guaranteed only by grouting reinforcement. The grouting problem is serious in a closed environment, and the grouting pressure is high, so that the cracking of a frozen wall and the integral bulging of the frozen wall are easily caused, the bulging and the cracking of the earth surface are caused, and potential safety hazards are brought to earth surface buildings; the grouting pressure is small, the aim of grouting and reinforcing the soil body cannot be achieved, the tunnel face stability is poor, and great risks are brought to the excavation of construction engineering.

Disclosure of Invention

The invention aims to overcome the risks and the defects in the horizontal grouting construction in the closed environment, and provides a horizontal grouting construction method in the closed environment, so that the purposes of safety, reliability, high efficiency, economy and practicability are achieved.

Furthermore, the periphery of the tunnel section is provided with a closed freezing ring, so that the grouting construction cannot damage the closed freezing ring, and horizontal grouting can be performed only on the side surface of a freezing wall, namely the front surface of the tunnel excavation section. In the grouting construction, a drain hole is firstly made, negative pressure drainage is adopted, water in a soil body is properly drained, then horizontal retreating type grouting is carried out, the drainage and the grouting are combined in the process, the grouting amount is slightly larger than the drainage amount, and the influence of the grouting on a frozen wall is monitored in real time by adopting a tension wire method in a pipe curtain. If other similar projects do not have pipe curtains, freezing structures, soil body layered settlement observation points can be buried in the earth surface, and the influence of grouting on the earth surface is closely observed.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a horizontal grouting construction method in a closed environment comprises the steps of grouting on the front face of a tunnel, wherein 50m is grouted in each cycle, and 10m is lapped; the first circulation is provided with 76 grouting holes, wherein the depth of B1-B9 holes is 15 meters, the depth of A1-A67 holes is 50 meters, the diffusion radius is 1.3m, the length of a drain hole is 40m, the grouting holes are arranged at the bottom, a flowmeter is arranged at the position of the drain hole, and the drainage quantity is counted; the method comprises the following steps:

(1) grouting equipment: drilling and grouting are integrated, and a drilling machine adopts a sectional drill rod to retreat grouting after drilling to a designed depth;

(2) grouting pressure: a1, A9-A22, A50-A53, A58-60, B1 and B9 grouting pressures are controlled to be 0.3-0.5 MPa, A4-A6, A25-A27, A37-A42, A45-A48, A54-A57, A62-A66 and B4-B6 grouting pressures are controlled to be 0.5-2 MPa, and the grouting pressures of other parts are controlled to be 0.5-1.5 MPa. Namely, the grouting pressure at the periphery of the tunnel is controlled to be 0.3-0.5 MPa, the grouting pressure at the central area is controlled to be 0.5-2 MPa, and the grouting pressure at other middle parts is controlled to be 0.5-1.5 MPa;

(3) grouting sequence: the outer side is towards the center, from top to bottom;

(4) grouting materials: the grouting material is based on the geological condition revealed by the drilling and the water yield, and proper slurry is selected. The silt or mucky soil, the general cohesive soil and the residual soil mainly comprise common cement paste and the cement-water glass double-liquid paste is taken as an auxiliary material; the sandy soil is mainly prepared from common cement-water glass double-fluid slurry and is assisted by common cement slurry. When the water yield is high, ordinary cement-water glass double-liquid slurry is adopted, and when the water yield is low, ordinary cement slurry is adopted. The front end 10m range adopts common cement-water glass double-liquid slurry. The peripheral holes are mainly made of common cement paste, and the middle holes are mainly made of common cement-water glass double-liquid paste;

(5) proportioning the slurry: ordinary cement paste W: c is 1.0, and the volume ratio of the ordinary cement-water glass double-liquid slurry is 1: 1;

(6) the pressure relief method comprises the following steps: combining the grouting sequence, arranging a pressure relief hole at the lower part of the grouting hole, placing a double-layer filter pipe after a drilling machine drills a horizontal hole, wherein the pipe length is 30-40 m, installing a flowmeter at the pipe orifice, installing a vacuum pump for accelerating the drainage speed, and performing negative pressure drainage;

(7) the grouting effect inspection method comprises the following steps: and (4) adopting an inspection hole method, drilling holes and coring, and measuring the water content and the strength of the core sample so as to judge the grouting effect.

The invention has the beneficial effects that:

1. the construction method for horizontal grouting in the closed environment is simple and convenient and has strong operability.

2. The invention combines drainage and grouting, and primary drainage can not be excessive to cause stratum settlement; and the grouting is carried out by combining the water discharge amount, so that the formation uplift caused by excessive grouting amount is avoided.

3. The invention provides the double control of grouting pressure and grouting quantity, and the deformation of the closed body and the stratum can be effectively controlled by adopting the principle of double control and slow speed in the construction process.

4. According to the invention, the grouting sequence is that the outer side is injected first and then the center, and the outer side is injected first, so that the influence of the grouting on the closed body is reduced.

5. The invention focuses on information-based construction, and the monitoring condition guides the adjustment of parameters such as grouting pressure, grouting speed, grouting amount and the like.

6. The invention can horizontally reinforce soil mass 50m at one time, which is beneficial to rapid centralized construction.

7. The construction method of horizontal grouting in the closed environment is safe, reliable, efficient, economical and practical.

Drawings

FIG. 1 is a schematic flow diagram of the present invention;

FIG. 2 is a sectional view showing the arrangement of grouting holes in a grouting tunnel face;

FIG. 3 is a sectional view of a final hole arrangement of grouting

FIG. 4 is a sectional view of the arrangement of the grouting final holes at 15 m.

Detailed Description

The present invention will be further described below, and it should be noted that the present embodiment is based on the technical solution and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the implementation manner.

As shown in fig. 1 to 4, the invention relates to a horizontal grouting construction method in a closed environment, grouting is carried out on the front surface of a tunnel, and the distance between every two grouting operations is 50m and 10 m; the first circulation is provided with 76 grouting holes, wherein the depth of B1-B9 holes is 15 meters, the depth of A1-A67 holes is 50 meters, the diffusion radius is 1.3m, the length of a drain hole is 40m, the grouting holes are arranged at the bottom, a flowmeter is arranged at the position of the drain hole, and the drainage quantity is counted; the method comprises the following steps:

(1) grouting equipment: drilling and grouting are integrated, and a drilling machine adopts a sectional drill rod to retreat grouting after drilling to a designed depth;

(2) grouting pressure: a1, A9-A22, A50-A53, A58-60, B1 and B9 grouting pressures are controlled to be 0.3-0.5 MPa, A4-A6, A25-A27, A37-A42, A45-A48, A54-A57, A62-A66 and B4-B6 grouting pressures are controlled to be 0.5-2 MPa, and the grouting pressures of other parts are controlled to be 0.5-1.5 MPa. Namely, the grouting pressure at the periphery of the tunnel is controlled to be 0.3-0.5 MPa, the grouting pressure at the central area is controlled to be 0.5-2 MPa, and the grouting pressure at other middle parts is controlled to be 0.5-1.5 MPa;

(3) grouting sequence: the outer side is towards the center, from top to bottom;

(4) grouting materials: the grouting material is based on the geological condition revealed by the drilling and the water yield, and proper slurry is selected. The silt or mucky soil, the general cohesive soil and the residual soil mainly comprise common cement paste and the cement-water glass double-liquid paste is taken as an auxiliary material; the sandy soil is mainly prepared from common cement-water glass double-fluid slurry and is assisted by common cement slurry. When the water yield is high, ordinary cement-water glass double-liquid slurry is adopted, and when the water yield is low, ordinary cement slurry is adopted. The front end 10m range adopts common cement-water glass double-liquid slurry. The peripheral holes are mainly made of common cement paste, and the middle holes are mainly made of common cement-water glass double-liquid paste;

(5) proportioning the slurry: ordinary cement paste W: c is 1.0, and the volume ratio of the ordinary cement-water glass double-liquid slurry is 1: 1;

(6) the pressure relief method comprises the following steps: combining the grouting sequence, arranging a pressure relief hole at the lower part of the grouting hole, placing a double-layer filter pipe after a drilling machine drills a horizontal hole, wherein the pipe length is 30-40 m, installing a flowmeter at the pipe orifice, installing a vacuum pump for accelerating the drainage speed, and performing negative pressure drainage;

(7) the grouting effect inspection method comprises the following steps: and (4) adopting an inspection hole method, drilling holes and coring, and measuring the water content and the strength of the core sample so as to judge the grouting effect.

Examples

Main process parameters

An orifice pipe: the outer diameter phi is 108mm, the wall thickness is 3.5mm, and the length is 1.2 m;

the diameter of the drill bit: 65 mm;

thirdly, aperture: 70 mm;

diffusion radius: 1.3 m;

single hole grouting amount: estimating according to the porosity of 15%, and determining the specific quantity on site;

initial setting time: single-fluid slurry for 3-5 h, double-fluid slurry for 1-1.5 min;

and seventhly, grouting final pressure: drawing up 0.3-2 MPa, and adjusting according to the field monitoring condition;

and the grouting termination conditions are as follows: pressure and grouting amount are controlled.

Ninthly, grouting speed: slow speed and fully spread the slurry

(1) Orifice tube installation

Before drilling, the vertical drilling angle (gradient) and the horizontal drilling angle (azimuth angle) of the grouting hole are calculated according to the start-end point coordinates of the grouting hole, and during construction, the drilling angle is adjusted at any time according to the calculation result and the actual construction effect. And arranging a sleeve at the starting point section of each hole, filling and bonding the sleeve and the hole wall by adopting epoxy resin, and keeping the exposed length of 30-40 cm. During drilling, the sleeve is firmly installed, and a sleeve orifice water-inrush preventing device matched with the selected drill rod is arranged at the front end of the drill rod.

And the hole-opening sleeve section adopts a core drilling machine to form a hole, and a phi 108 orifice pipe is installed.

(2) Pressure relief hole

The drilling machine adopts a drilling and injection integrated machine to drill, the hole depth is 30-40 m, a double-layer sleeve is inserted after a drill bit is pulled out, and a flowmeter is installed at the end of the sleeve. And after the arrangement of the pressure relief holes is finished, grouting holes can be drilled for grouting. In order to accelerate the drainage speed, a vacuum pump can be installed for negative pressure drainage.

(3) Drilling holes

The drilling machine adopts a drilling and grouting integrated machine, the grouting sequence is from inside to outside, and the recording is made along with the operation class while drilling. The recorded content is: hole number, footage, starting and stopping mileage, drilling tool size, soil layer name, position where water gushes out and water injection amount. And analyzing and judging the engineering geology and hydrogeology conditions in front of the excavation surface according to the soil layer samples, the drilling speed and the water inrush and leakage conditions, and taking the analyzed and judged engineering geology and hydrogeology conditions as the basis for taking what technical measures for the next excavation.

The holes must be accurately positioned according to the design of the test scheme. When the hole is drilled, the pressure is slightly increased, the speed is slow, the water quantity is large, and the drilling hole is prevented from being obliquely drilled and the direction is prevented from being wrongly drilled; before the grouting holes are formed, lofting is carried out on the spot according to coordinates, the error range of the coordinates of the starting point of each hole is not more than 20cm, and the final hole is not more than 50 cm;

before the operator leaves the working surface, the operator must not drill; the drilling machine cannot be shifted during operation; after the hole depth exceeds 30m, high-pressure and rapid drilling cannot be performed, and hole collapse or rod breakage accidents are prevented.

(4) Grouting

Before grouting, a grouting test is carried out in a rock stratum under similar geological conditions, and indexes such as slurry filling rate, grouting amount, slurry gel finishing time, slurry diffusion radius, grouting final pressure and the like are determined preliminarily.

And after the drilling machine drills to the designed depth, the drilling machine adopts a sectional drill rod to carry out backward grouting, and the grouting section is 3m each time.

And preparing slurry according to the selected parameters, wherein the grouting pipe needs to be checked firstly, and then is connected to a grouting system after the grouting pipe is confirmed to be unblocked. After the grouting system is connected with a drill rod, a valve is opened, and a grouting pump is started to perform grouting according to the procedures of firstly diluting and then thickening, (grouting amount) firstly enlarging and then reducing, firstly cementing single-fluid slurry and then injecting double-fluid slurry. And when the grouting pressure reaches the design value, maintaining for 2-3 min, stopping grouting when the grouting amount reaches the design amount, cleaning the pipeline, closing the valve, and withdrawing the pipe after the double-liquid-slurry is initially set for next-stage grouting. And determining the length of the grouting subsection in the hole according to the geological condition of the drilling hole, wherein 3m is generally suitable.

The grouting operation of a hole section is generally continuously finished, the grouting operation is not interrupted, forced interruption caused by mechanical faults, power failure, water cut, equipment and the like is avoided as much as possible, and the grouting operation is repeated after a drill hole is cleaned to the original depth for intentionally interrupting the grouting operation caused by intermittent grouting and stopping grout leakage and the like.

(5) Checking grouting effect

And taking out the soil sample by adopting a core taking machine, observing the hole treading effect, measuring the water content and the strength of the soil sample and judging the grouting effect. After the purposes of reinforcing soil and improving excavation environment are achieved, the diaphragm wall can be broken and the next procedure is carried out.

Monitoring items

Pipe inspection, pipe curtain level, vertical displacement, surface vertical displacement, underground water level, frozen ring temperature change and water yield. The pipe curtain horizontal and vertical displacement measuring points are mainly arranged in 2#, 4#, 36#, 34#, and 32# pipes, the arrangement section extends 50m (grouting section) from the pipe orifice inwards, and a group of measuring points are arranged at the bolt joint of each pipe section. The water yield is measured by installing a flowmeter, and the flow is recorded.

(1) Monitoring frequency: the vertical displacement of the earth surface is 1/2 h, the displacement of the pipe curtain is 1/2 h, and the temperature change of the freezing ring is monitored in real time.

(2) Early warning value control

Grouting was stopped immediately when:

grouting in a pipe and on the ground surface;

the accumulated deformation of the pipe curtain exceeds 5 mm;

and the local temperature change of the freezing ring is overlarge.

(3) Monitoring method

Patrol in pipe

Plaster is smeared in the gap of the flange plate, whether the plaster cracks or not is observed, and whether the pipe joint has an opening angle or not is judged. And (4) observing the soil improvement grouting hole, and reporting the water burst and slurry burst phenomena immediately once the water burst and slurry burst phenomena are discovered.

Tension wire method for measuring deformation of pipe joint

Because the place is narrow and small in the pipe curtain tube coupling, the operation of conventional method is difficult, considers monitoring precision and ageing demand, and horizontal displacement adopts the lead wire method to monitor, and concrete operating procedure is as follows:

1) respectively welding a steel wire bolt fastener on the pipe wall of the pipe section hole and the pipe wall at the farthest position (about 70m) which can be seen inwards, and completely twisting the fasteners by using a fastener to ensure that the steel wire is stretched, straightened and stabilized;

2) selecting a steel wire with the diameter of 1mm to be arranged on a fastener, and paying attention to control the tightening degree of the steel wire to prevent disconnection;

3) pipe curtain horizontal displacement measuring point marks are arranged at the joints of the pipe joints, the corresponding steel wires are simultaneously provided with marks, the marks on the pipe wall are positioned at one side of grouting, a pair of mark connecting lines are basically vertical to the steel wires, the verticality of the steel wires can be controlled by a square, the pair of marks is a group of horizontal displacement measuring points, and a group of horizontal displacement measuring points is arranged at the joint of each pipe joint;

4) measuring the distances of a group of horizontal displacement measuring points at different time intervals after the measuring points are arranged, measuring for 3 times, taking the average value as an initial value, and estimating to read to 0.5 mm;

5) and determining the sign of the deformation amount, wherein the sign is plus if the pipe wall measuring point deforms to the grouting position, and the sign is minus if the pipe wall measuring point deforms away from the grouting position.

Various other changes and modifications to the above-described embodiments and concepts will become apparent to those skilled in the art from the above description, and all such changes and modifications are intended to be included within the scope of the present invention as defined in the appended claims.

Claims (1)

1. A horizontal grouting construction method in a closed environment is characterized in that grouting is performed on the front face of a tunnel, 50m is performed every cycle, and 10m is overlapped; the first circulation is provided with 76 grouting holes, wherein the depth of B1-B9 holes is 15 meters, the depth of A1-A67 holes is 50 meters, the diffusion radius is 1.3m, the length of a drain hole is 40m, the grouting holes are arranged at the bottom, a flowmeter is arranged at the position of the drain hole, and the drainage quantity is counted; the method comprises the following steps:

(1) grouting equipment: drilling and grouting are integrated, and a drilling machine adopts a sectional drill rod to retreat grouting after drilling to a designed depth;

(2) grouting pressure: a1, A9-A22, A50-A53, A58-60, B1, B9 grouting pressure is controlled to be 0.3-0.5 MPa, A4-A6, A25-A27, A37-A42, A45-A48, A54-A57, A62-A66, B4-B6 grouting pressure is controlled to be 0.5-2 MPa, other part grouting pressure is controlled to be 0.5-1.5 MPa, namely the grouting pressure at the periphery of the tunnel is controlled to be 0.3-0.5 MPa, the grouting pressure at the central area is controlled to be 0.5-2 MPa, and the grouting pressure at other middle parts is controlled to be 0.5-1.5 MPa;

(3) grouting sequence: the outer side is towards the center, from top to bottom;

(4) grouting materials: the grouting material takes the geological condition revealed by the drilling and the water yield as the basis, and selects proper slurry, wherein the silt or mucky soil, the general cohesive soil and the residual soil mainly comprise common cement slurry and the cement-water glass double-fluid slurry is used as the auxiliary; the sandy soil is mainly prepared from common cement-water glass double-liquid slurry, the common cement slurry is used as an auxiliary material, the common cement-water glass double-liquid slurry is adopted when the water yield is high, the common cement slurry is adopted when the water yield is low, the common cement-water glass double-liquid slurry is adopted within the range of 10m at the front end, the common cement slurry is mainly adopted in the peripheral holes, and the common cement-water glass double-liquid slurry is mainly adopted in the middle holes;

(5) the ratio of the grout to the common grout W to C is 1.0, and the volume ratio of the common cement to the water glass double-grout is 1: 1;

(6) the pressure relief method comprises the following steps: combining the grouting sequence, arranging a pressure relief hole at the lower part of the grouting hole, placing a double-layer filter pipe after a drilling machine drills a horizontal hole, wherein the pipe length is 30-40 m, installing a flowmeter at the pipe orifice, installing a vacuum pump for accelerating the drainage speed, and performing negative pressure drainage;

(7) the grouting effect inspection method comprises the following steps: and (4) adopting an inspection hole method, drilling holes and coring, and measuring the water content and the strength of the core sample so as to judge the grouting effect.