CN111399373A - GIN grouting flow pressure intelligent control method - Google Patents

Abstract

A GIN grouting flow pressure intelligent control method comprises the following control modes, wherein a flow pressure product constant is defined to be P x Q, and the flow pressure product constant is a value determined by a GIN value; p-grouting pressure, Q is fluid volume flow, the grouting stage is divided into five stages A, B, C, D, E according to different grouting pressures, and the control modes of the stages are different. By adopting the intelligent GIN grouting flow pressure control method, grouting pressure is regulated in different areas in a semi-quantitative mode. The grouting pressure control method provides theoretical basis and practical operation means for pressure control in the grouting process, improves controllability of the grouting process, and enables practically completed grouting pressure control to be more easily expected.

Description

GIN grouting flow pressure intelligent control method

Technical Field

The invention belongs to the technical field of buildings, relates to a grouting technology, and particularly relates to a GIN grouting flow pressure intelligent control method.

Background

Grouting is the process of pouring some solidified materials, such as cement, lime or other chemical materials, into the ground rock and soil within a certain range under the foundation to fill cracks and pores in the rock and soil, prevent the leakage of the foundation and improve the integrity, strength and rigidity of the rock and soil. In floodgates, dams, dikes and other water retaining buildings, a foundation impervious curtain is constructed by a grouting method, which is a main foundation treatment measure of hydraulic buildings; the slurry with fluidity and gelatination property is pressed into the stratum or the gap of the building according to a certain proportion requirement by drilling (or pre-buried pipes) to be cemented and hardened into a whole, thereby achieving the engineering purposes of seepage prevention, consolidation and reinforcement.

The GIN (grouting Intensity number) grouting method can also be called as grouting Intensity value grouting method, and the GIN is kept to be a constant value in the whole grouting process of a grouting section.

In a grouting section, the energy consumption is approximately equal to the product of grouting pressure P and the cumulative injection quantity V per unit length, namely P × V, the value P × V is called a GIN value (grouting strength value), if the grouting pressure is MPa and the cumulative injection quantity per unit length is L/m, the GIN value can be expressed as MPa ×L/m, for example, the GIN value is 200, namely P × V is 200(MPa ×L/m).

Disclosure of Invention

In order to overcome the technical defects in the prior art, the invention discloses a GIN grouting flow pressure intelligent control method.

The intelligent GIN grouting flow pressure control method comprises the following control modes,

defining a flow-pressure product constant, P x Q, which is a value determined by the GIN value;

wherein P-grouting pressure, Q is fluid volume flow,

according to different grouting pressures, the grouting stage is divided into five stages A, B, C, D, E, and the control mode of each stage is as follows:

section A, the pressure range is that P is more than or equal to 0 and less than or equal to P1,

adopting rapid pressure boosting operation, boosting speed V1, and flow-limiting grouting;

and B, section: the pressure range is P1-P2;

adopting continuous slow boosting operation, the boosting speed is V2, and V2 is less than V1, and the flow-limiting grouting liquid

And C, section: the pressure range is P2-P3

Keeping the pressure stable around P3 and keeping the pressure unchanged;

and D, section: p is not less than P3_MAX

Keeping the pressure and the flow stable and unchanged;

e, section: p ═ P_MAX

Keeping the pressure and the flow stable and unchanged;

P_MAXand Q_MAXThe pressure maximum and the flow maximum under the constraint of critical conditions are respectively, and the relation of each stage P, Q is constrained by an equation P Q;

the endpoint values for the various phases are defined as:

Q₃＝(1-ΔB)Q_MAX

Q₄＝Q_MAX；

P₃＝(1-ΔA)P_MAX

P₄＝P_MAX

the first and second reduction amounts Δ a and Δ B are constant values set in advance.

Preferably, the first reduction amount Δ a is 0.1, and the second reduction amount Δ B is 0.1.

By adopting the intelligent GIN grouting flow pressure control method, grouting pressure is regulated in different areas in a semi-quantitative mode. The grouting pressure control method provides theoretical basis and practical operation means for pressure control in the grouting process, improves controllability of the grouting process, and enables practically completed grouting pressure control to be more easily expected.

Drawings

Fig. 1 is a schematic diagram of an embodiment of the intelligent GIN grouting flow pressure control method.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

The invention is mainly used for adjusting and controlling the pressure in the GIN grouting method in real time, so that the pressure in the grouting process is consistent with an expected value as much as possible and the construction requirement is met.

Pressure regulation plays a very important role in grouting systems. When the pressure in the hole exceeds the set pressure value, the opening degree of the regulating valve is regulated. The purpose of stabilizing the pressure is achieved. The regulating valve is a throttling element with variable local resistance, and the pressure loss of incompressible liquid is known according to the energy conservation principle as follows:

wherein the meaning of each parameter is:

pressure loss of delta P regulating valve

ξ_Q-regulating valve drag coefficient

Average speed of omega-fluid

Rho-fluid density

P₁,P₂Pressure before and after the regulating valve

The average velocity of the fluid is:

wherein: q-fluid volumetric flow, flow for short.

Flow cross-sectional area of F-regulating valve

The two formulas of the combined vertical type (1) and (2) can obtain the flow equation of the regulating valve

Wherein: a is a constant related to the dimension selected for each parameter.

According to the formula (3), a nonlinear relation exists between the fluid volume flow Q and the pressure.

In a grouting section, the energy consumption is approximately equal to the product of the grouting pressure P and the cumulative injection quantity V per unit length, i.e. P × V, the value P × V is called the GIN value (grouting strength value). if the grouting pressure is in MPa and the cumulative injection quantity per unit length is in L/m, the GIN value can be expressed in MPa ×L/m.

In the GIN grouting method, the GIN is kept to be a constant value in the whole grouting process of a grouting section, the energy consumption is approximately equal to the product of the grouting pressure P and the accumulated injection quantity V per section length, namely P × V is a constant value, and under the condition that the time is usually a fixed value, the grouting strength value can be directly converted into a relation between the grouting pressure P and the injection quantity Q, and a constant is defined, wherein the constant value is only related to the GIN value and the grouting time under the engineering definition.

＝P*Q (4)。

Wherein, the P-grouting pressure is MPa;

q-fluid volumetric flow, unit L/Min.

According to the technical specification of hydraulic construction cement grouting construction (D L/T5148-2017), the step pressure boosting or the sequential pressure boosting can be adopted under the condition that the maximum pressure and the maximum flow are not exceeded by definite manual control.

Furthermore, there is an allowable maximum value of pressure P, constrained by the critical conditions that ensure that the bedrock is not destroyed_MAXMaximum sum flow Q_MAX，

According to the actual setting of the first reduction amount Δ a and the second reduction amount Δ B, the first reduction amount Δ a and the second reduction amount Δ B may take 0.1 and 0.15, respectively, depending on the values of the flow rate and the pressure, for example, when the flow rate and the pressure are 30L/min and 0.1mpa, respectively.

Under the constraint of equation (4), four pressure points P1-P4 and corresponding flow points Q1-Q4 are set,

Q₃＝(1-ΔB)Q_MAX

Q₄＝Q_MAX；

P₃＝(1-ΔA)P_MAX

P₄＝P_MAX

the grouting stage can be divided into 5 stages A, B, C, D, E according to the pressure, as shown in fig. 1, and different grouting flow rates Q are adopted for different pressure stages, and the curve in fig. 1 is the curve of equation (4).

Wherein the pressure value of the section A is more than or equal to 0 and less than or equal to P1

At this time, the pressure P is very small and tends to 0, and is generally less than or equal to 0.1 MPa.

At this time, rapid pressure raising operation can be adopted, for example, the pressure raising speed V1 can be 0.1 MPa/s, the flow limiting grouting is adopted, the flow Q is less than or equal to 30L/min, and the flow is correspondingly adjusted according to the formula (4) and the pressure change.

In practice, if the pressure is still not significantly changed after 15 minutes or 300L is reached, the slurry changing operation may be performed.

And B, section: p is not less than P1 and not more than P2

At the moment, the pressure P is smaller and is generally less than or equal to 0.3 MPa;

the method adopts continuous slow pressure raising operation, for example, the pressure raising speed V2 can be 0.02 MPa/s, the flow rate Q can still set the maximum value, such as Q is less than or equal to 30L/min, the flow rate Q lasts for 15 minutes or the accumulated injection amount reaches 300L, and the grouting operation is carried out if the pressure is not obviously changed.

And C, section: p is not less than P2 and not more than P3

At this time, the grouting stage is stabilized, the pressure is stable, and the flow is stable.

And (3) adopting PQ control to stably grout the injection rate, gradually increasing the grouting pressure when the injection amount is increased, and controlling the grouting pressure to be stable near P3 when the pressure is increased to P3 so that the injection rate Q is continuously reduced to be less than or equal to 5L/min.

And D, section: p is not less than P3_MAX

The pressure is close to the design pressure P_MAXAnd stabilizing the pressure P, and regulating to ensure that the volume flow Q of the fluid is less than or equal to 3L/min.

E, section: p ═ P_MAX

The pressure reaches the design pressure P_MAXAnd stabilizing the pressure P to ensure that the volume flow Q of the fluid is less than or equal to 1L/min, and finishing grouting after continuing for 30 minutes.

By adopting the intelligent GIN grouting flow pressure control method, grouting pressure is regulated in different areas in a semi-quantitative mode. The grouting pressure control method provides theoretical basis and practical operation means for pressure control in the grouting process, improves controllability of the grouting process, and enables practically completed grouting pressure control to be more easily expected.

The foregoing is directed to preferred embodiments of the present invention, wherein the preferred embodiments are not obviously contradictory or subject to any particular embodiment, and any combination of the preferred embodiments may be combined in any overlapping manner, and the specific parameters in the embodiments and examples are only for the purpose of clearly illustrating the inventor's invention verification process and are not intended to limit the scope of the invention, which is defined by the claims and the equivalent structural changes made by the description and drawings of the present invention are also intended to be included in the scope of the present invention.

Claims (2)

1. A GIN grouting flow pressure intelligent control method is characterized by comprising the following control modes,

defining a flow-pressure product constant, P x Q, which is a value determined by the GIN value;

wherein P-grouting pressure, Q is fluid volume flow,

according to different grouting pressures, the grouting stage is divided into five stages A, B, C, D, E, and the control mode of each stage is as follows:

section A, the pressure range is that P is more than or equal to 0 and less than or equal to P1,

adopting rapid pressure boosting operation, boosting speed V1, and flow-limiting grouting;

and B, section: the pressure range is P1-P2;

adopting continuous slow boosting operation, the boosting speed is V2, and V2 is less than V1, and the flow-limiting grouting liquid

And C, section: the pressure range is P2-P3

Keeping the pressure stable around P3 and keeping the pressure unchanged;

and D, section: p is not less than P3_MAX

Keeping the pressure and the flow stable and unchanged;

e, section: p ═ P_MAX

Keeping the pressure and the flow stable and unchanged;

P_MAXand Q_MAXPressure maximum and flow maximum under the constraint of critical conditions, and the relation of each stage P, QConstrained by the equation P x Q;

the endpoint values for the various phases are defined as:

Q₃＝(1-ΔB)Q_MAX

Q₄＝Q_MAX；

P₃＝(1-ΔA)P_MAX

P₄＝P_MAX

the first and second reduction amounts Δ a and Δ B are constant values set in advance.

2. The control method according to claim 1, wherein the first decrease amount Δ a is 0.1 and the second decrease amount Δ B is 0.5.

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