阅读说明：本技术 袖阀注浆的工艺 (Sleeve valve grouting process ) 是由 徐小诗 牛新平 翁训龙 刘如诺 边强 何文龙 温元灶 于 2021-07-23 设计创作，主要内容包括：一种袖阀注浆的工艺,其特征是,a)原地形钻孔取样,得出所要施工区域的地质、作业条件的勘探图；b)根据地基土层的物理力学性质计算注浆参数；c)根据注浆参数及勘探图中的地基土构成进行分层,并选择合理的注浆层先后顺序；d)通过试验确定不同配比套壳料强度增长龄期；f)根据注浆压力,确定套壳料配比；g)对应套壳料强度适时开始注浆。本发明通过合理的分层注浆顺序,所设定的注浆参数适应现场环境,施工质量高,总注浆行程为现有总注浆行程一半,节省了近一半的工作量,且每次注浆压力以及注浆量相同,操作工只要知道每次注浆起点深度和终点深度,无需再通过勘探图调整注浆参数,以此降低操作工的劳动强度,对操作工技术水平要求降低。(A technology for grouting sleeve valves is characterized by comprising the following steps of a) drilling and sampling original terrain to obtain an exploration map of geology and operation conditions of a to-be-constructed area; b) calculating grouting parameters according to the physical and mechanical properties of the foundation soil layer; c) layering according to the grouting parameters and the foundation soil composition in the exploration map, and selecting a reasonable grouting layer sequence; d) the strength growth age of the shell materials with different proportions is determined through tests; f) determining the shell material ratio according to the grouting pressure; g) and (5) grouting at the right time corresponding to the strength of the casing material. According to the invention, through a reasonable layered grouting sequence, the set grouting parameters are adapted to the field environment, the construction quality is high, the total grouting stroke is half of the existing total grouting stroke, nearly half of workload is saved, the grouting pressure and the grouting amount are the same each time, an operator only needs to know the starting point depth and the end point depth of each grouting, and the grouting parameters do not need to be adjusted through an exploration map, so that the labor intensity of the operator is reduced, and the requirement on the technical level of the operator is lowered.)

1. A technology for grouting sleeve valves is characterized by comprising the following steps of a) drilling and sampling original terrain to obtain an exploration map of geology and operation conditions of a to-be-constructed area; b) calculating grouting parameters according to the physical and mechanical properties of the foundation soil layer; c) layering according to the grouting parameters and the foundation soil composition in the exploration map, and selecting a reasonable grouting layer sequence; d) the strength growth age of the shell materials with different proportions is determined through tests; f) determining the shell material ratio according to the grouting pressure; g) and (5) grouting at the right time corresponding to the strength of the casing material.

2. The sleeve valve grouting process according to claim 1, wherein the layering according to geological and operating conditions is realized by designing grouting layers by determining the physical and mechanical properties of strata with different depths through a sampling body, and the grouting sequence is selected mainly according to grouting pressure and secondarily according to grouting quantity.

3. The sleeve valve grouting process according to claim 2, wherein when the calculated grouting pressure of the upper foundation is lower than that of the lower foundation, grouting is started from the upper foundation to form a network or framework for reinforcing soil bodies by the slurry of the upper foundation, grouting of the lower foundation is performed to effectively prevent slurry leakage caused by lifting and even cracking of the upper foundation due to the fact that the grouting pressure of the lower foundation is too high, and grouting is performed from bottom to top when the calculated grouting pressures of the upper foundation and the lower foundation are the same.

4. The sleeve valve grouting process according to claim 1, wherein the grouting parameters comprise grouting pressure and grouting amount.

5. The sleeve valve grouting process according to claim 4, wherein the grouting pressure is related to factors such as depth of a reinforced soil layer, compactness of the soil layer, slurry viscosity, grouting speed and grouting amount, the higher grouting pressure can be deviated under the condition of ensuring the safety of a stratum structure, the actual grouting pressure is higher than the calculated grouting pressure, the difference between the actual grouting pressure and the calculated grouting pressure is not more than 0.02MPa, and the preliminarily determined minimum grouting pressure is calculated by adopting a passive soil pressure theoretical formula:

in the formula: gamma z is soil mass gravity, KN/m³；

The internal friction angle of the soil body;

c is the cohesion of the soil body, kPa;

h is the thickness of the reinforcing soil layer, m.

6. The sleeve valve grouting process according to claim 5, wherein the grouting amount is determined as follows: and calculating by a grouting amount formula according to the geological condition.

In the formula: q isAmount of injected, m³；

V is the volume of the soil body, m³；

dg is the relative density of the soil particles;

e0 is the initial void ratio;

omega 0 is the natural water content of the soil;

omega p is the plastic limit water content of the soil;

and (c) is the compression factor, taken as 1.20.

7. The sleeve valve grouting process according to claim 1, wherein in the depth of a foundation to be grouted, an exploration chart shows that the foundation has three layers, the upper layer is a miscellaneous fill layer, the middle layer is a silt layer, and the lower layer is sandy cohesive soil, and the grouting process is characterized in that: firstly calculating grouting parameters

Grouting pressure formula:

grouting amount formula:

performing a test in a field environment, determining the strength growth age of the casing materials with different proportions, and selecting a proper casing material according to grouting pressure; determining a grouting sequence, grouting for the first time: performing primary grouting on the 1 st layer of miscellaneous filling soil and the 2 nd layer of sludge from bottom to top, wherein the open-loop pressure is greater than the strength of the casing material on the same day, the grouting pressure is restored to a calculated value after the casing material in a grouting area is crushed, the grouting pressure and the grouting amount are unchanged until top-sealing grouting on the uppermost layer is completed, and the grouting amount on the 1 st layer is completely injected within one day; stopping grouting for 1 day until the top layer is sealed stably; and (3) grouting for the second time: grouting the 2 nd layer sludge and the 3 rd layer sandy cohesive soil from bottom to top, wherein the open loop pressure is greater than the strength of the casing material on the same day, after the casing material in the grouting area is crushed, the grouting pressure is controlled to be the calculated value of the grouting pressure of the 3 rd layer sandy cohesive soil, the grouting pressure and the grouting amount are not changed, and the grouting is stopped until the grouting height is raised to the top elevation of the sludge layer, and is finished in one day, wherein the grouting amount is the total grouting amount of the 3 rd layer; and (3) suspending grouting for 1 day, and grouting for the third time when the strength of the shell material is increased to be higher than the set grouting pressure: and (5) performing third grouting on the sludge layer of the 2 nd layer from bottom to top to finish grouting of all grouting amounts of the sludge layer of the 2 nd layer.

8. The sleeve valve grouting process according to claim 7, wherein the first grouting is calculated as: grouting the first layer of miscellaneous fill layer and the second layer of sludge layer at the pressure of 0.17Mpa and the cement amount of 55kg/m, and grouting for the second time: grouting the silt layer of the 2 nd layer and the sandy cohesive soil of the 3 rd layer under the pressure of 0.77Mpa, grouting cement quantity of 55kg/m, and grouting for the third time: sludge layer 2: the grouting pressure is 1.0Mpa, the grouting cement amount is 219kg/m, and a shell material is selected, wherein the cement: clay: water 1:1.2:2.3, strength of 0.25Mpa, 0.5Mpa, 0.78Mpa and 1.09Mpa in 1, 3, 5 and 7 days under natural curing, and first grouting is started on the 1 st day: the step 1 of miscellaneous fill and the step 2 of sludge layer are carried out from bottom to top, the open loop pressure is greater than 0.25Mpa, the grouting pressure is adjusted to 0.17Mpa after casing materials of a grouting area are crushed, the grouting cement amount is 55kg/m, the grouting pressure and the grouting amount are not changed until top sealing grouting is finished in one day; stopping grouting for 3 days until the top layer is sealed stably; second grouting on day 5: grouting the 2 nd layer sludge and the 3 rd layer sandy cohesive soil from bottom to top, wherein the open loop pressure is greater than 0.78Mpa, the grouting pressure is controlled to be 0.77Mpa after casing materials in a grouting area are crushed, the grouting cement amount is 55kg/m, the grouting pressure and the grouting amount are not changed, and the grouting is stopped until the grouting height is raised to the top elevation of the sludge layer, and the grouting is finished within one day; grouting is suspended for 1 day, and when the strength of casing materials is increased to be higher than the set grouting pressure, grouting is performed for the third time on the 7 th day: and (3) performing third grouting on the sludge layer of the 2 nd layer from bottom to top, wherein the grouting pressure is 1.0Mpa, and the grouting cement amount is 219kg/m, so that the grouting of all grouting amounts of the sludge layer of the 2 nd layer is completed.

Technical Field

The invention belongs to engineering construction, in particular to a grouting process.

Background

The sleeve valve grouting is a common method for treating foundations, particularly large building foundations (such as airports and the like), in-situ drilling and sampling are carried out, an exploration map of geology and operation conditions of a to-be-constructed area is obtained, as shown in figure 1, the permeability coefficient of the foundation in a natural state increases along with the depth, grouting is carried out from bottom to top, but an artificial land formed by artificial landfill exists at present, as shown in figure 1, three obvious layers are arranged under the ground 18 meters away from the surface, and the permeability coefficient indexes of all soil layers are shown in a table 1.

TABLE 1

According to the conventional process (as shown in figure 2): drilling a hole by adopting a drill bit with the diameter of 110mm and mud protection wall, wherein the verticality deviation is not more than 1%, the hole depth is 20cm below the bottom boundary, the diameter of the sleeve valve pipe is 50mm, and the sleeve valve pipe is exposed out of the ground surface by 30 cm. 1.5 meters of the top layer of the foundation is an empty grouting section, the lower part of the foundation is a uniform grouting section, the upper layer of the foundation gradually rises from bottom to top by a lift range of 0.33 meters, the upper layer of the foundation is 3.2 meters and is a miscellaneous fill layer, and the grouting pressure is 0.3 MPa; the middle 4.8 m is a sludge layer, and the grouting pressure is 1.0 Mpa; the lower layer 10m is sandy cohesive soil, and the grouting pressure is 2 Mpa; a plurality of grouting holes are drilled on the surface, the distance between every two adjacent holes is generally 1.4m (namely the diameter of a grouting pile body is 1.4m), grouting can be generally carried out for 3 times, casing materials can meet the condition of natural curing for 3 days, grouting is carried out for three times, the bottom elevation of a grouting section is from bottom to top to the top elevation of the grouting section (the bottom elevation of an empty grouting section) in each grouting, and the interval time of each grouting is not less than 24 hours. The first grouting is 50% of the designed total grouting amount, the second grouting is 30% of the designed total grouting amount, the third grouting is 20% of the designed total grouting amount, and the grouting pressure is as follows: the open loop pressure is 1MPa, and the grouting pressure is 0.3-2 MPa. Namely, as shown in fig. 2, designing the cement consumption of 240kg per meter of grouting, and performing primary grouting on the bottom elevation of a foundation grouting section from bottom to top on day 4, wherein the lift of a grouting pipe is 0.33 meter until the top elevation of the grouting section (the bottom elevation of an empty grouting section) and the cement consumption of 120kg per meter (depth) of grouting; and on the 5 th day, performing second grouting on the bottom elevation of the designed grouting section of the foundation from bottom to top until the top elevation of the grouting section (the bottom elevation of the empty grouting section), wherein the consumption of cement for grouting per meter is 72kg, the grouting pipe is lifted upwards, and the operation flow is the same as that of the first grouting. And (4) performing third grouting on the bottom elevation of the foundation grouting section from bottom to top to the top elevation of the grouting section (the bottom elevation of the empty grouting section) on the 6 th day, wherein the cement consumption per meter of grouting is 48kg, a grouting pipe is lifted upwards, and the operation flow is the same as that of the first grouting and the second grouting.

The casing material has the function of forming a protective layer with certain strength around the sleeve valve pipe, the casing material is crushed at the position of the sleeve valve pipe with the grout outlet during grouting, and the casing materials at the upper part and the lower part still have certain strength and can prevent the grout from flowing up and down, so that the grout can only transversely flow in a certain range. The grouting pipe is used for pressing the grout into the rock-soil layer through certain pressure, and when the grout enters the grout outlet of the sleeve valve pipe through the grouting pipe, the rubber cap wrapped on the periphery of the grout outlet is jacked up under the action of the pressure. Along with the gathering of thick liquid, after pressure reached certain degree, the peripheral rubber cap of grout outlet thoroughly expanded, and the cover shell material is crowded garrulous, and the thick liquid extrudees the stratum in through the gap of the cover shell material that is crowded garrulous, forms splitting slip casting. Therefore, the quality of the casting strength of the casing materials is the key for ensuring the success of grouting, and the casing materials are required to not only press open the filling materials under certain pressure for transverse grouting, but also prevent the grout from flowing out of the ground along the hole wall or the pipe wall during high-pressure grouting. The mechanical strength of the casing material is required to meet the grouting requirement, namely, the slurry mixing is prevented and the ring opening is also required. Single-hole casing material pouring amount: q is K pi x (drilling radius R2-sleeve valve tube outer radius R2) x grouting section height, the drilling radius R is 110mm, the sleeve valve tube outer radius R is 50mm, the grouting section height is 18m (including 1.5m empty grout section), K is loss coefficient, and is generally 1.2-2.0, and the engineering is 1.3. The existing sleeve valve grouting casing material has the defects that: the shell material ratio is a fixed value, and the ratio is cement: clay: water-1: 1.5: 1.88.

In the implementation process according to the traditional process, the fact that the cement consumption of a silt layer is insufficient is found, a standard experiment cannot meet design requirements, coring is carried out on the silt layer to find that silt still presents a flow-plastic-soft-plastic state, and scientific researchers preliminarily consider that the situation is caused by insufficient grouting pressure and insufficient grouting amount. However, when the grouting pressure and the grouting amount are increased during the secondary test, the foundation is lifted too much, so that a series of problems of deformation of underground pipelines, cracking of the ground surface, slurry bleeding and the like are caused.

In the process of finding the reason, the test on the proportioning strength of the shell materials in the construction environment (natural health preservation) as shown in fig. 1 shows that table 2 is obtained

TABLE 2

The designed grouting process does not notice that the casing and the grouting pressure have deviation, and the selected casing material ratio is not combined with the factors of the physical and mechanical properties of the main rock-soil layer of the foundation, the sleeve valve grouting, the construction characteristics, the grouting parameters, the construction environment and the like, so that the inconsistency of the sleeve valve grouting casing material ratio and the construction process is one of the reasons for poor grouting quality. When the strength of the casing material reaches 0.5Mpa in the third day of the process (three days when the strength of the casing material is aged), when the first grouting is carried out on the bottom elevation of the designed grouting section of the foundation from bottom to top to the top elevation of the grouting section, the grouting pressure is 2Mpa as the lower layer of 10m sandy cohesive soil is firstly grouted, the strength of the casing material is only 0.5Mpa at the moment, the strength is insufficient, after the casing material is crushed at the position of a slurry outlet hole of the casing valve pipe by the cement slurry, the strength of the casing material cannot prevent the upward and downward flow of the slurry, and similarly, when the grouting pressure of a sludge layer is 1.0Mpa, the upward and downward flow of the slurry cannot be prevented, so that the slurry flows out of the ground surface along the wall of the hole wall or the casing valve pipe to form string slurry.

In summary, the above grouting method mainly has the following disadvantages:

(1) the grouting sequence is from bottom to top of the bottom elevation of the grouting section to the top elevation of the grouting section, the grouting sequence is not adjusted along with the foundation condition, so that the foundation soil body cracks, and cement slurry flows out of the ground surface through the soil body cracks to form a slurry overflow phenomenon;

(2) the grouting amount is uniform, and the grouting pressure is inaccurate. The grouting amount of a sludge layer is insufficient due to no adjustment according to actual conditions, the detection of a grouting finished product is unqualified, and the foundation is violently lifted due to the excessive grouting amount of a miscellaneous fill layer.

(3) The casing material is single in proportion, and a casing material strength test is not carried out, so that the grouting progress is not adjusted according to the actual condition of the casing material strength during construction, and once the casing material strength is insufficient, the upward flow of the slurry cannot be prevented, so that the slurry flows out of the ground surface along the wall of the hole wall or the wall of the sleeve valve pipe to form slurry string; if the strength of the casing material is too high, the cement slurry cannot smoothly crush the casing material and is extruded into the stratum through gaps of the crushed casing material to form split grouting.

(4) The set grouting parameters cannot adapt to the field geological environment, the grouting pressure and the grouting amount need to be changed according to different stratum geological changes every time, the requirements on the labor concentration degree and the professional technical level of operators are high, and the construction quality is poor.

Disclosure of Invention

The sleeve valve grouting process aims to overcome the defects that the grouting construction quality is poor due to the fact that no attention is paid to the field geological environment, the setting of the grouting sequence is not related to grouting parameters such as grouting pressure and the like, and the influence of the timely strength of the casing material on the grouting construction quality is not paid attention to in the conventional grouting process.

The technical scheme adopted by the invention is a sleeve valve grouting process, which is characterized by comprising the following steps of a) drilling and sampling original terrain to obtain an exploration map of geological and operating conditions of a to-be-constructed area; b) calculating grouting parameters according to the physical and mechanical properties of the foundation soil layer; c) layering according to the grouting parameters and the foundation soil composition in the exploration map, and selecting a reasonable grouting layer sequence; d) the strength growth age of the shell materials with different proportions is determined through tests; f) determining the shell material ratio according to the grouting pressure; g) and (5) grouting at the right time corresponding to the strength of the casing material.

After the exploration map is obtained, technicians set reasonable grouting layer sequence and grouting parameters for foundation soil composition according to different geological conditions instead of constant bottom-to-top grouting. The strength growth age of the shell materials with different proportions is determined on site; determining the shell material ratio according to the grouting pressure; and (5) grouting at the right time corresponding to the strength of the casing material. Accurate grouting is realized to the influence of on-the-spot environment to cover shell material intensity to guarantee the slip casting quality.

The layering according to geology and operation conditions is to design a grouting layer by determining physical and mechanical properties of stratums with different depths by a sampling body, and the basis of selecting a grouting sequence is mainly grouting pressure and assisted by grouting quantity.

When the calculated grouting pressure of the upper foundation is smaller than that of the lower foundation, the upper foundation is grouted firstly to form a network or a framework for reinforcing the soil body by the slurry of the upper layer, then the lower layer grouting is carried out to effectively prevent the upper foundation from being lifted or even cracked to cause slurry overflow due to the overlarge grouting pressure of the lower layer, and when the calculated grouting pressure of the upper foundation and the lower foundation is the same, the upper foundation is grouted from bottom to top.

The grouting pressure is related to factors such as the depth of a reinforced soil layer, the compactness of the soil layer, the slurry viscosity, the grouting speed and the grouting amount, can be deviated to higher grouting pressure under the condition of ensuring the safety of a stratum structure, the actual grouting pressure is larger than the calculated grouting pressure, the difference between the actual grouting pressure and the calculated grouting pressure is not larger than 0.02Mpa, and the preliminary determined minimum grouting pressure is calculated by adopting a passive soil pressure theoretical formula:

in the formula: gamma z is soil mass gravity, KN/m³；

The internal friction angle of the soil body;

c is the cohesion of the soil body, kPa;

h is the thickness of the reinforcing soil layer, m.

Determining the grouting amount: according to grouting pressure and geological conditions by formula

In the formula: q is the grouting amount, m³；

V is the volume of the soil body, m³；

dg is the relative density of the soil particles;

e0 is the initial void ratio;

omega 0 is the natural water content of the soil;

omega p is the plastic limit water content of the soil;

and (c) is the compression factor, taken as 1.20.

A sleeve valve grouting process is based on the following practical conditions: in the foundation depth to be grouted, the exploration diagram shows that the foundation has three layers, the upper layer is a mixed filling soil layer, the middle layer is a silt layer, the lower layer is sandy cohesive soil, the design is carried out, and the grouting process is as follows: firstly calculating grouting parameters

Grouting pressure formula:

grouting amount formula:

performing a test in a field environment, determining the strength growth age of the casing materials with different proportions, and selecting a proper casing material according to grouting pressure; determining a grouting sequence, grouting for the first time: performing primary grouting on the 1 st layer of miscellaneous filling soil and the 2 nd layer of sludge from bottom to top, wherein the open-loop pressure is greater than the strength of the casing material on the same day, the grouting pressure is restored to a calculated value after the casing material in a grouting area is crushed, the grouting pressure and the grouting amount are unchanged until top-sealing grouting on the uppermost layer is completed, and the grouting amount on the 1 st layer is completely injected within one day; stopping grouting for 1 day until the top layer is sealed stably; and (3) grouting for the second time: grouting the 2 nd layer sludge and the 3 rd layer sandy cohesive soil from bottom to top, wherein the open loop pressure is greater than the strength of the casing material on the same day, after the casing material in the grouting area is crushed, the grouting pressure is controlled to be the calculated value of the grouting pressure of the 3 rd layer sandy cohesive soil, the grouting pressure and the grouting amount are not changed, and the grouting is stopped until the grouting height is raised to the top elevation of the sludge layer, and is finished in one day, wherein the grouting amount is the total grouting amount of the 3 rd layer; and (3) suspending grouting for 1 day, and grouting for the third time when the strength of the shell material is increased to be higher than the set grouting pressure: and (5) performing third grouting on the sludge layer of the 2 nd layer from bottom to top to finish grouting of all grouting amounts of the sludge layer of the 2 nd layer.

Calculating to obtain the first grouting: grouting the first layer of miscellaneous fill layer and the second layer of sludge layer at the pressure of 0.17Mpa and the cement amount of 55kg/m, and grouting for the second time: grouting the silt layer of the 2 nd layer and the sandy cohesive soil of the 3 rd layer under the pressure of 0.77Mpa, grouting cement quantity of 55kg/m, and grouting for the third time: sludge layer 2: the grouting pressure is 1.0Mpa, the grouting cement amount is 219kg/m, and a shell material is selected, wherein the cement: clay: water 1:1.2:2.3, strength of 0.25Mpa, 0.5Mpa, 0.78Mpa and 1.09Mpa in 1, 3, 5 and 7 days under natural curing, and first grouting is started on the 1 st day: the step 1 of miscellaneous fill and the step 2 of sludge layer are carried out from bottom to top, the open loop pressure is greater than 0.25Mpa, the grouting pressure is adjusted to 0.17Mpa after casing materials of a grouting area are crushed, the grouting cement amount is 55kg/m, the grouting pressure and the grouting amount are not changed until top sealing grouting is finished in one day; stopping grouting for 3 days until the top layer is sealed stably; second grouting on day 5: grouting the 2 nd layer sludge and the 3 rd layer sandy cohesive soil from bottom to top, wherein the open loop pressure is greater than 0.78Mpa, the grouting pressure is controlled to be 0.77Mpa after casing materials in a grouting area are crushed, the grouting cement amount is 55kg/m, the grouting pressure and the grouting amount are not changed, and the grouting is stopped until the grouting height is raised to the top elevation of the sludge layer, and the grouting is finished within one day; grouting is suspended for 1 day, and when the strength of casing materials is increased to be higher than the set grouting pressure, grouting is performed for the third time on the 7 th day: and (3) performing third grouting on the sludge layer of the 2 nd layer from bottom to top, wherein the grouting pressure is 1.0Mpa, and the grouting cement amount is 219kg/m, so that the grouting of all grouting amounts of the sludge layer of the 2 nd layer is completed.

The first grouting of the sludge is carried out by adopting smaller calculated grouting pressure, and the aim is to form solidification by utilizing the chemical reaction formed by cement paste and water in the sludge in a flow molding state.

And (3) adopting larger calculation grouting pressure for the second grouting of the sludge, and aiming at filling the solidified sludge in a flow plastic state (gradually forming a soft plastic state, increasing the strength of a soil body, enhancing the capability of resisting grouting compressive stress, and enabling silt soil to present contractibility under the action of cement paste) and the cavity part of the sludge in the soft plastic state by using the cement paste.

The third grouting of the sludge adopts the grouting pressure which is as large as possible and lower than the strength of the timely casing material, and aims to gradually present a hard-plastic state between the sludge in a flow-plastic state and the sludge in a soft-plastic state, wherein the solidified sludge is filled with cement paste at the moment (the soil body of the sludge in the hard-plastic state is increased in strength in a soft-plastic state, the grouting pressure stress resistance is higher, and the integral saturation of the soil body is higher), and the soil layer is subjected to fracturing grouting by pressurization.

The invention has the advantages that: through a reasonable layered grouting sequence, the set grouting parameters adapt to the field environment, and the construction quality is high. The total grouting stroke of the invention is half of the prior total grouting stroke, nearly half of workload is saved, and each grouting pressure and the grouting amount are the same, and an operator only needs to know the starting point depth and the end point depth of each grouting and does not need to adjust grouting parameters through an exploration chart, thereby reducing the labor intensity of the operator and lowering the requirement on the technical level of the operator.

Drawings

FIG. 1 is a geological survey of an area to be grouted

FIG. 2 shows a conventional grouting process

FIG. 3 Process design first slip casting of the invention

FIG. 4 Process design of the invention second slip casting

FIG. 5 Process design of the invention third slip casting

Detailed Description

The present invention is described in detail below with reference to the drawings so that those skilled in the art can more understand the present invention.

A sleeve valve grouting process comprises a) drilling and sampling original terrain to obtain an exploration map of geological and operating conditions of a to-be-constructed area; b) calculating grouting parameters according to the physical and mechanical properties of the foundation soil layer; c) layering according to the grouting parameters and the foundation soil composition in the exploration map, and selecting a reasonable grouting layer sequence; d) the strength growth age of the shell materials with different proportions is determined through tests; f) determining the shell material ratio according to the grouting pressure; g) and (5) grouting at the right time corresponding to the strength of the casing material.

The layering according to geology and operation conditions is to design a grouting layer by determining physical and mechanical properties of stratums with different depths by a sampling body, and the basis of selecting a grouting sequence is mainly grouting pressure and assisted by grouting quantity. Grouting is generally initiated from a foundation layer having a low grouting pressure.

When the calculated grouting pressure of the upper foundation is smaller than that of the lower foundation, the upper foundation is grouted firstly, so that the slurry on the upper foundation forms a network or a framework for reinforcing the soil body, then the lower grouting is carried out, the phenomenon that the upper foundation is lifted up or even cracks to cause slurry overflow due to the fact that the lower grouting pressure is too large can be effectively prevented, and when the calculated grouting pressure of the upper foundation and the lower foundation is the same, the upper grouting is carried out from bottom to top.

The grouting pressure is related to factors such as the depth of a reinforced soil layer, the compactness of the soil layer, the slurry viscosity, the grouting speed and the grouting amount, can be deviated to higher grouting pressure under the condition of ensuring the safety of a stratum structure, and the minimal grouting pressure is preliminarily determined to be calculated by adopting a passive soil pressure theoretical formula:

in the formula: gamma z is soil mass gravity, KN/m³；

The internal friction angle of the soil body;

c is the cohesion of the soil body, kPa;

h is the thickness of the reinforcing soil layer, m.

Determining the grouting amount: according to grouting pressure and geological conditions by formula

In the formula: q is the grouting amount, m³；

V is the volume of the soil body, m³；

dg is the relative density of the soil particles;

e0 is the initial void ratio;

omega 0 is the natural water content of the soil;

omega p is the plastic limit water content of the soil;

and (c) is the compression factor, taken as 1.20.

The exploration chart of the sleeve valve grouting process is shown in figure 1, and detailed exploration reports are shown in table 3

TABLE 3 detailed survey report of test period

According to the following practical conditions: in the depth of a foundation to be grouted, an exploration diagram of the foundation shows that the foundation has three layers, wherein the upper layer is 3.2 meters and is a miscellaneous fill layer, the middle layer is 4.8 meters and is a silt layer, and the lower layer is 10 meters and is sandy cohesive soil. The grouting process comprises the following steps:

firstly, calculating grouting pressure: the grouting pressure is related to factors such as the depth of a reinforced soil layer, the compactness of the soil layer, the viscosity of slurry, the grouting speed, the grouting amount and the like. If the grouting pressure is small, the splitting effect cannot be achieved; if the grouting pressure is too large, the reinforced soil body is not uniform, the surrounding sleeve valve pipes are extruded to cause slurry stringing, and even the foundation structure is damaged to cause the phenomena of lifting, cracking and slurry bleeding of the foundation. Under the condition of guaranteeing stratum structure safety, can be partial to higher slip casting pressure, be favorable to improving the stone intensity of the groutability of thick liquid and thick liquid like this, consider the pressure loss of grout in the transportation process in the slip casting pipe, actual slip casting pressure ratio calculates grouting pressure big, and the difference of the two is not more than 0.02Mpa, and minimum grouting pressure adopts passive earth pressure theoretical formula to calculate:

grouting pressure formula:

in the formula: gamma z is soil mass gravity, KN/m³；

The internal friction angle of the soil body;

c is the cohesion of the soil body, kPa;

h is the thickness of the reinforcing soil layer, m.

Table 4 table of physical and mechanical property test report of main rock and soil layer of test section

According to the above table, the physical index γ z of the miscellaneous fill layer is 18.5KN/m³，

Therefore, the method comprises the following steps:

therefore, the fracturing grouting pressure P of the miscellaneous fill layer (the depth of the bottom layer is 3.2 meters) in the area is selected to be 0.17 MPa. According to Table 4, the physical index γ z of the sludge layer was 16.5KN/m³，h＝8.0m,c＝7.3kPa,Therefore, the method comprises the following steps:

therefore, the fracturing grouting pressure P of the sludge layer (the bottom depth of the layer is 8.0 meters) in the region is selected to be 0.17 MPa. According to the above table, the physical index γ z of sandy cohesive soil is 19.3KN/m³，h＝18.0m,c＝21.5kPa,Therefore, the method comprises the following steps:

the fracturing grouting pressure P of the sandy cohesive soil layer (the depth of the bottom of the layer is 18 meters) in the area is selected to be 0.77 MPa.

Calculation of grouting amount

Without local engineering experience, the grouting amount is calculated by the formula (2):

in the formula: q is the grouting amount, m³；

V is the volume of the soil body, m³；

dg is the relative density of the soil particles;

e0 is the initial void ratio;

omega 0 is the natural water content of the soil;

omega p is the plastic limit water content of the soil;

and (c) is the compression factor, taken as 1.20.

Calculating according to the diameter of a grouting pile body of 1.4m, substituting into a formula, and taking physical indexes of sludge, wherein dg is 2.70, e0 is 1.521, ω 0 is 58.5%, ω P is 36.0%, and ═ 1.20.

Therefore, the method comprises the following steps:

therefore, the temperature of the molten metal is controlled,grouting amount of each linear meter of the sludge layer in the region is 0.435m³The cement amount was 329kg/m corresponding to a water-cement ratio of 1.0.

Similarly, the diameter of the grouting pile body is 1.4m, the formula is substituted, the physical index of the sandy cohesive soil is taken, dg is 2.66, e0 is 0.787, ω 0 is 27.9%, ω P is 25.3%, and ═ 1.20.

Therefore, the method comprises the following steps:

therefore, the grouting amount of the sandy cohesive soil layer per linear meter in the area is 0.072m³When the water-cement ratio is 1.0, the cement consumption is 54.4kg/m, and the design is 55 kg/m.

Calculating according to the diameter of the grouting pile body of 1.4m, substituting the diameter into the formula, taking the physical index of the miscellaneous fill soil,

dg＝2.70,e0＝0.913,ω0＝30.2％,ωP＝27.4％，∫＝1.20。

therefore, the method comprises the following steps:

therefore, the grouting amount of the miscellaneous fill layer per linear meter in the area is 0.073m³When the water-cement ratio is 1.0, the cement consumption is 55.1kg/m, and the cement is designed to be 55kg/m by rounding.

Performing a strength test on the casing material to determine the grouting time, and analyzing the test result of the strength of the casing material by using a computer full-automatic constant-pressure bending and compression testing machine

Cement: clay: 1:1:2.3, three groups of components, and the curing time is as follows: 1 day, 3 days, 5 days and 7 days

Cement: clay: 1:1.2:2.3, three groups of components, and the curing time is as follows: 1 day, 3 days, 5 days and 7 days

Cement: clay: 1:0.8:2.3, three groups of components, and the curing time is as follows: 1 day, 3 days, 5 days and 7 days

Cement: clay: 1:1.5:2.3, three groups of components, and the curing time is as follows: 1 day, 3 days, 5 days and 7 days

Cement: clay: 1:1.5:1.88, three groups, and the curing time is as follows: 1 day, 3 days, 5 days and 7 days

The strength of the jacket material was measured at different mix ratios, and the results are shown in Table 5

Table 5 Shell Material Strength at different mix proportions

As can be seen from table 5: the shell material with the same water-cement ratio has higher strength as the content of bentonite is higher; the shell material with the same mixing proportion has the strength slightly lower than that of standard health preservation.

According to the actual situation, the invention selects the shell material: cement: clay: the strength of water is 1:1.2:2.3, under the condition of natural curing, the strength of the water is 0.25Mpa, 0.5Mpa, 0.78Mpa and 1.09Mpa in 1, 3, 5 and 7 days respectively, and the grouting process is designed as follows: 1.5 meters of the top layer is an empty slurry section, and the first grouting is started on the 1 st day: for the 1 st layer of miscellaneous filling soil (the part below the empty slurry section) and the 2 nd layer of sludge, the depth of the bottom layer is 8.00 m, the process is carried out from bottom to top, the open loop pressure is greater than 0.25Mpa, the grouting pressure is adjusted to 0.17Mpa after the casing material of the grouting area is crushed, the grouting cement amount is 55kg/m (the total amount of miscellaneous filling soil layers, namely the grouting of miscellaneous filling soil layers is completed at one time), the grouting pressure and the grouting amount are not changed until the top layer top sealing grouting is completed, and the process is completed within one day; the calculated grouting pressure of the sandy cohesive soil is 0.762MPa, so that the grouting is suspended for 3 days in order to enable the casing material strength to reach the grouting pressure, and the casing material strength of the sandy cohesive soil meets the calculated grouting pressure after the top sealing of the uppermost layer is stable; and (5) performing secondary grouting: grouting the 2 nd layer sludge and the 3 rd layer sandy cohesive soil from bottom to top, wherein the open loop pressure is greater than 0.78Mpa (because the strength of a casing material is 0.78Mpa), the grouting pressure is controlled to be 0.77Mpa after the casing material in the grouting area is crushed, the grouting cement amount is 55kg/m (the total amount of the sandy cohesive soil layers, namely the grouting of the sandy cohesive soil layers is finished at one time), the grouting pressure and the grouting amount are not changed, and the grouting is stopped until the grouting height is raised to the top elevation of the sludge layer, and the grouting is finished in one day; also, when the shell strength reached 1.09Mpa on day 7, the slurry was injected for the third time on day 7: and (3) performing third grouting on the sludge layer of the 2 nd layer from bottom to top, wherein the grouting pressure is 1.0Mpa, and the grouting cement amount is 219kg/m, so that the grouting of all grouting amounts of the sludge layer of the 2 nd layer is completed.

The invention selects the strength of the casing with the proper pressure according to the grouting pressure to perform grouting, solves the problem of grout leakage existing at present, and simultaneously enhances the strength of the foundation of the upper layer along with the time because the first grouting is performed on the upper layer, as shown in the following table

TABLE 6 Strength of the upper ground

During the second grouting, the strength of the upper miscellaneous fill layer is naturally maintained for four days, and reaches 12Mpa, so that the slurry bleeding phenomenon cannot occur when the second grouting pressure of the sludge reaches 0.77 Mpa.

And (3) determining the third grouting pressure of the sludge: because the sludge layer is subjected to twice grouting at different times and different pressures, the grouting pressure can not be calculated by using a formula, and the larger grouting pressure is more beneficial to the sludge layer treatment effect, so the grouting pressure which is as large as possible and lower than the strength of timely casing materials is adopted, and the aim is that the flow-plastic sludge and soft-plastic sludge filled and solidified by cement paste gradually show a hard-plastic state (the soil body strength of the hard-plastic sludge is increased in a softer plastic state, the grouting pressure stress resistance is stronger, and the integral saturation of the soil body is stronger), and the soil layer is subjected to split grouting by pressurizing.

During the third grouting, the strength of the upper miscellaneous fill layer is naturally maintained for six days, and the strength reaches 15MPa, so that the slurry bleeding phenomenon cannot occur when the third grouting pressure of the sludge reaches 1 MPa.

The invention completes the whole grouting in three times, but completes all grouting amount at one time for the miscellaneous fill soil and sandy cohesive soil layer with less grouting amount, and performs grouting with increasing pressure through three times for the sludge layer (sludge: dark gray, saturated, flow plastic-soft plastic state) with larger grouting amount and smaller permeability coefficient. The total grouting stroke of the invention is 6.5+14.8+ 4.8-26.1 m, while the total grouting stroke of the prior art is 16.5+16.5+ 16.5-49.5 m, which saves nearly half of the workload, and the grouting pressure and the grouting amount are the same each time, and an operator only needs to know the starting point depth and the end point depth of each grouting, and does not need to adjust the grouting parameters through an exploration chart, thereby reducing the labor intensity of the operator and lowering the requirement on the technical level of the operator.

The first grouting of the sludge adopts smaller grouting pressure, and aims to form solidification by utilizing the chemical reaction formed by cement paste and water in the sludge in a flow molding state.

The second grouting of the sludge adopts larger grouting pressure, and aims to fill solidified sludge in a flow plastic state (gradually forming a soft plastic state, increasing the strength of a soil body, enhancing the capability of resisting grouting compressive stress, and enabling silt to present contractibility under the action of cement paste) and a cavity part of the sludge in the soft plastic state by using the cement paste.

The method is characterized in that the maximum grouting pressure is adopted for the third grouting of the sludge, the purpose is that the solidified sludge in the flow plastic state and the solidified sludge in the soft plastic state filled with cement paste gradually show a hard plastic state (the soil body of the sludge in the hard plastic state is increased in strength in a soft plastic state, the grouting pressure stress resistance is higher, the integral saturation of the soil body is higher), and the soil layer is subjected to fracturing grouting by pressurization.

The method is applied to the formal construction stage, 40 points of the original surface standard penetration are accumulated, finished product 9113 holes are completed, the total is 87932.10 m, 185 points of the third-party detection standard penetration are accumulated according to the design requirements, and the statistics of the completion conditions (detection center standard penetration detection) are shown in the table 7:

TABLE 7 (detection center run-through detection) completed statistics

The grouting quality inspection adopts a standard penetration test standard: the detection time is preferably 28 days after grouting is finished, the detection holes are arranged in the middle of the 4 grouting holes, the minimum value after the sludge layer is treated is required to be not less than 5 strokes, the minimum value after other strata are treated is more than 2 strokes (including 2 strokes) of the minimum value of the original foundation, and the detection number is not less than 5 holes. The grouting detection quantity is 2% of the grouting holes.

Marking and penetrating the original surface of the field: the average impact number of the miscellaneous fill layer and the sandy cohesive soil is 8 impacts, the average impact number of the soft plastic sludge layer is only 1 impact, and the average impact number of the flow plastic sludge layer is 0 impact.

The invention detects the standard penetration by a third party after foundation treatment: the average impact number of the miscellaneous fill layer and the sandy cohesive soil reaches 18 impacts, the average impact number of the soft plastic sludge layer is 7 impacts, and the average impact number of the flow plastic sludge layer meets 6 impacts.

The rest of the parts which are not described are the same as the prior art.

The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications and equivalents made on the basis of the technical idea of the present invention fall within the protection scope of the present invention.