A method and device for analyzing the stability of the bottom of a narrow foundation pit against heave

Abstract

The present invention discloses a method and device for analyzing the stability of the bottom of a narrow foundation pit against heave, which relates to the technical field of geotechnical engineering. Among them, the method for analyzing the stability of the bottom of a narrow foundation pit against heave is applicable to anchored and braced narrow foundation pits, and includes the following steps: determining whether the current foundation pit is a narrow foundation pit; when the current foundation pit is a narrow foundation pit, dividing the soil mass into slices based on the principle of the Swedish slice method; analyzing the forces acting on the divided slices and calculating the safety factor for the stability of the bottom of the foundation pit against heave. The present invention can avoid excessive embedment depth of the retaining structure and has better social and economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering, and particularly relates to a method and device for analyzing the anti-heave stability of the bottom of a narrow foundation pit. Background Art

[0002] The analysis of foundation pit stability is one of the key links in foundation pit design. In the industry, the overall stability, anti-heave stability, anti-overturning stability, etc. of the foundation pit are mainly checked according to the relevant provisions of the "Technical Specification for Building Foundation Pit Support" (JGJ 120-2012). Among them, the anti-heave stability checking methods for foundation pits with anchor-pulling or bracing retaining structures include two aspects:

[0003] (1) The weight of the soil outside the foundation pit is greater than the shear strength of the soil inside the foundation pit, causing the soil to slide and resulting in the upward heave failure of the soil inside the pit, corresponding to the analysis of the anti-heave stability of the bottom of the foundation pit wall. The checking formula for the anti-heave stability of the bottom of the wall provided by the specification is as follows:

[0004]

[0005]

[0006]

[0007] (2) Assuming that the soil on both sides of the foundation pit slides along the circular arc sliding surface passing through the bottom of the retaining structure, resulting in the toe failure of the foundation pit, corresponding to the analysis of the anti-heave stability of the bottom of the foundation pit. The checking formula for the anti-heave stability of the bottom of the pit provided by the specification is as follows:

[0008]

[0009] See Figure 1 As shown, for the existing second stability analysis method, the following deficiencies exist:

[0010] Assuming that the foundation pit is a semi-infinite body and the circular arc sliding surface slides out from the soil at the bottom of the pit, the beneficial effect of the self-weight of the soil on the opposite side is not considered. This assumption is more in line with building foundation pits because the excavation width of building foundation pits is much larger than the excavation depth. However, for foundation pits such as subway tunnels, highway tunnels, railway tunnels, and municipal tunnels, which are usually long and narrow in distribution, the excavation width of the foundation pit is often smaller than the excavation depth, which does not conform to the above assumption. If the above assumption is still used for calculation, it may cause the required embedded depth of the retaining structure to be too large, resulting in design waste. Summary of the Invention

[0011] Aiming at the defects existing in the prior art, the first aspect of the present invention provides a method for analyzing the anti-heave stability of the bottom of a narrow foundation pit, which can avoid excessive embedding of the retaining structure and has better social and economic benefits.

[0012] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0013] A method for analyzing the anti-uplift stability of a pit bottom applicable to a narrow foundation pit comprises the following steps:

[0014] Determine whether the current foundation pit is a narrow foundation pit;

[0015] When the current foundation pit is a narrow foundation pit, the soil is divided into strips based on the Swedish strip method;

[0016] Conduct stress analysis on the divided strips and calculate the safety factor of the pit bottom's anti-uplift stability.

[0017] In some embodiments, determining whether the current foundation pit is a narrow foundation pit includes:

[0018] With the lowest support point as the center, draw an arc passing through the bottom of the retaining structure wall. When the radius of the arc is greater than the width of the foundation pit, it is determined to be a narrow foundation pit.

[0019] In some embodiments, when the current foundation pit is a narrow foundation pit, dividing the soil into strips based on the Swedish strip method includes:

[0020] Divide the soil outside the foundation pit into 9 strips with a width of 1m;

[0021] Divide the soil inside the foundation pit into 6 strips with a width of 1m;

[0022] The soil on the opposite side of the foundation pit is divided into three strips with a width of 1m.

[0023] In some embodiments, the performing of force analysis on the divided strips and calculating the safety factor of the pit bottom anti-uplift stability includes:

[0024] According to the formula:

[0025]

[0026] Calculate the safety factor of pit bottom stability against uplift ;

[0027] Where, is the safety factor of the pit bottom's stability against uplift;

[0028] is the deadweight of the i-th soil strip outside the foundation pit, calculated according to the natural gravity;

[0029] is the deadweight of the jth soil strip inside and on the opposite side of the foundation pit, calculated based on the natural gravity;

[0030] is the width of the i-th soil strip outside the foundation pit;

[0031] is the width of the j-th soil strip on the inner side and the opposite side of the foundation pit;

[0032] is the length of the sliding circular arc surface of the i-th soil strip on the outside of the foundation pit;

[0033] is the length of the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit;

[0034] is the angle between the normal line and the perpendicular line at the midpoint of the sliding circular arc surface of the i-th soil strip on the outside of the foundation pit;

[0035] is the angle between the normal line and the perpendicular line at the midpoint of the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit;

[0036] is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip on the outside of the foundation pit;

[0037] is the internal friction angle of the soil at the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit;

[0038] is the cohesion of the soil at the sliding circular arc surface of the i-th soil strip on the outside of the foundation pit;

[0039] is the cohesion of the soil at the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit;

[0040] is the ground surcharge borne by the i-th soil strip on the outside of the foundation pit.

[0041] In some embodiments, the depth of the foundation pit is 15 m and the width is 12 m.

[0042] In some embodiments, the unit weight of the soil is 19 kN / m 3 , the cohesion is 12 kPa, the internal friction angle is 18°, and the surcharge is 20 kPa.

[0043] The second aspect of the present invention provides an analysis device for the bottom heave stability of a narrow foundation pit, which can avoid excessive embedment depth of the retaining structure and has better social and economic benefits.

[0044] To achieve the above object, the technical solution adopted by the present invention is:

[0045] An analysis device for the bottom heave stability of a narrow foundation pit, comprising:

[0046] A judgment module, which is used to judge whether the current foundation pit is a narrow foundation pit;

[0047] A calculation module, which is used to divide the soil mass into slices based on the principle of the Swedish slice method when the current foundation pit is a narrow foundation pit, and perform a force analysis on the divided slices to calculate the safety factor of the bottom heave stability of the foundation pit.

[0048] In some embodiments, the judgment module is configured to: draw an arc passing through the bottom of the retaining structure wall with the lowest support fulcrum as the center of the circle, and when the radius of the arc is greater than the width of the foundation pit, it is determined as a narrow foundation pit.

[0049] In some embodiments, when the current foundation pit is a narrow foundation pit, the calculation module is used to divide the soil mass into slices based on the principle of the Swedish slice method, including:

[0050] Divide the soil mass outside the foundation pit into 9 slices with a width of 1 m;

[0051] Divide the soil mass inside the foundation pit into 6 slices with a width of 1 m;

[0052] Divide the soil mass on the opposite side of the foundation pit into 3 slices with a width of 1 m.

[0053] In some embodiments, the calculation module performs a force analysis on the divided slices and calculates the safety factor of the bottom heave stability of the foundation pit, including:

[0054] According to the formula:

[0055]

[0056] Calculate the safety factor of the bottom heave stability of the foundation pit ;

[0057] In the formula, is the safety factor of the bottom heave stability of the foundation pit;

[0058] is the self-weight of the i-th soil slice outside the foundation pit, calculated according to the natural unit weight;

[0059] is the self-weight of the j-th soil slice inside and on the opposite side of the foundation pit, calculated according to the natural unit weight;

[0060] is the width of the i-th soil slice outside the foundation pit;

[0061] is the width of the j-th soil slice inside and on the opposite side of the foundation pit;

[0062] is the length of the sliding arc surface of the i-th soil slice outside the foundation pit;

[0063] is the length of the sliding arc surface of the j-th soil slice inside and on the opposite side of the foundation pit;

[0064] is the included angle between the normal line and the perpendicular line at the midpoint of the sliding circular arc surface of the i-th soil strip outside the foundation pit;

[0065] is the included angle between the normal line and the perpendicular line at the midpoint of the sliding circular arc surface of the j-th soil strip inside and on the opposite side of the foundation pit;

[0066] is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip outside the foundation pit;

[0067] is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip inside and on the opposite side of the foundation pit;

[0068] is the cohesion of the soil at the sliding circular arc surface of the i-th soil strip outside the foundation pit;

[0069] is the cohesion of the soil at the sliding circular arc surface of the j-th soil strip inside and on the opposite side of the foundation pit;

[0070] is the ground surcharge borne by the i-th soil strip outside the foundation pit.

[0071] Compared with the prior art, the advantages of the present invention are as follows:

[0072] The method for analyzing the stability of the bottom heave resistance of a narrow foundation pit in the present invention determines whether the current foundation pit is a narrow foundation pit; when the current foundation pit is a narrow foundation pit, based on the principle of the Swedish slice method, the soil mass is divided into slices; the forces acting on the divided slices are analyzed, and the safety factor of the bottom heave resistance stability is calculated. Thus, it can avoid the over-deep embedment of the retaining structure and has better social and economic benefits. Description of the Drawings

[0073] Figure 1 is a diagram showing the calculation of the stability of the bottom heave resistance of an existing foundation pit;

[0074] Figure 2 is a flow chart of the method for analyzing the stability of the bottom heave resistance of a narrow foundation pit applicable to the present invention;

[0075] Figure 3 is a diagram showing the calculation of the stability of the bottom heave resistance of a narrow foundation pit applicable to the anchor-pulled and braced retaining structures in the embodiment of the present invention;

[0076] Figure 4 is the calculation model of the narrow foundation pit in the embodiment of the present invention;

[0077] Figure 5 is the calculation model provided according to the existing specifications for comparison in the embodiment of the present invention. Detailed Embodiments

[0078] For the purposes of making the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0079] In order to solve the problem that the existing specifications' calculation formulas for the anti-heave stability of the narrow foundation pit bottom of the anchored and braced retaining structures fail to reflect the beneficial effect of the self-weight of the soil on the opposite side, resulting in an underestimated anti-heave safety factor of the foundation pit bottom, an excessive embedment depth of the required retaining structure, and design waste, based on the calculation principle of the Swedish slice method, the present invention fully considers the beneficial effect of the soil on the opposite side of the foundation pit on the anti-heave stability of the foundation pit bottom, and provides an analysis method for the anti-heave stability of the narrow foundation pit applicable to the anchored and braced retaining structures.

[0080] See Figure 1 As shown, the embodiments of the present invention provide an analysis method for the anti-heave stability of the narrow foundation pit applicable to the anchored and braced narrow foundation pits, and the method includes the following steps:

[0081] S1. Determine whether the current foundation pit is a narrow foundation pit.

[0082] See Figure 3 As shown, it gives the calculation diagram of the anti-heave stability of the narrow foundation pit bottom applicable to the anchored and braced retaining structures. In Figure 3 it mainly involves the outside of the foundation pit 1, the inside of the foundation pit 2, the opposite side of the foundation pit 3, the foundation pit retaining structure 4, the retaining structure on the opposite side of the foundation pit 5, the uppermost support 6, the lowermost support 7, the lowermost support fulcrum 8, and the sliding arc 9.

[0083] In this embodiment, the judgment principle of the narrow foundation pit of the anchored and braced retaining structures. See Figure 3 and Figure 4 As shown, with the lowermost support fulcrum 8 as the center, draw an arc passing through the bottom of the foundation pit retaining structure 4. When the arc radius is greater than the foundation pit width, it is determined as a narrow foundation pit.

[0084] S2. When the current foundation pit is a narrow foundation pit, divide the soil mass into slices based on the principle of the Swedish slice method.

[0085] The Swedish slice method, namely the Swedish circular arc sliding surface slice method, is to divide the soil mass above the assumed sliding surface into n vertical soil slices, conduct force and moment balance analysis on the forces acting on each soil slice, and calculate the safety factor of the soil mass stability in the limit equilibrium state.

[0086] See Figure 4As shown in the figure, in this embodiment, the soil outside the foundation pit is divided into strips with a width of 1 m, numbered 1, 2, 3... 9; the soil inside the foundation pit is divided into strips with a width of 1 m, numbered 10, 11, 12... 15; the soil on the opposite side of the foundation pit is divided into strips with a width of 1 m, numbered 1', 2', 3'. It can be understood that the width and quantity of the soil division can be reasonably set according to needs, and the embodiments of the present invention do not limit this here.

[0087] S3. Conduct a force analysis on the divided strips and calculate the safety factor of the bottom heave stability of the foundation pit.

[0088] For the force analysis of the divided strips, reference can be made to Figure 3 As shown in the figure. Based on the force analysis and the balance of forces, the safety factor of the bottom heave stability of the foundation pit can be calculated.

[0089] Specifically, in the embodiments of the present invention, according to the formula:

[0090]

[0091] Calculate the safety factor of the bottom heave stability of the foundation pit ;

[0092] In the formula, is the safety factor of the bottom heave stability of the foundation pit;

[0093] is the self-weight of the i-th soil strip outside the foundation pit, calculated according to the natural unit weight, with the unit of kN;

[0094] is the self-weight of the j-th soil strip inside and on the opposite side of the foundation pit, calculated according to the natural unit weight, with the unit of kN;

[0095] is the width of the i-th soil strip outside the foundation pit, with the unit of m;

[0096] is the width of the j-th soil strip inside and on the opposite side of the foundation pit, with the unit of m;

[0097] is the length of the slip arc surface of the i-th soil strip outside the foundation pit, with the unit of m;

[0098] is the length of the slip arc surface of the j-th soil strip inside and on the opposite side of the foundation pit, with the unit of m;

[0099] is the angle between the normal line and the vertical line at the midpoint of the slip arc surface of the i-th soil strip outside the foundation pit, with the unit of (°);

[0100] is the included angle between the normal line and the vertical line at the midpoint of the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit, with the unit of (°);

[0101] is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip on the outer side of the foundation pit, with the unit of (°);

[0102] is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip on the inner side and the opposite side of the foundation pit, with the unit of (°);

[0103] is the cohesion of the soil at the sliding circular arc surface of the i-th soil strip on the outer side of the foundation pit, with the unit of kPa.

[0104] is the cohesion of the soil at the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit, with the unit of kPa.

[0105] is the ground surcharge borne by the i-th soil strip on the outer side of the foundation pit, with the unit of kPa.

[0106] The following takes a specific example to illustrate:

[0107] In this embodiment, the depth of the foundation pit is 15 m, and the width of the foundation pit is 12 m. The foundation pit adopts a supported retaining structure, and the embedded depth of the retaining structure is 15 m. The soil layer is regarded as a homogeneous soil mass, with a soil unit weight of 19 kN / m 3 , a cohesion of 12 kPa, an internal friction angle of 18°, and an overloading of 20 kPa.

[0108] According to the soil division method and related calculation formulas in the above steps, the anti-heave stability of the bottom of the pit is calculated. The specific calculation process is shown in the following table:

[0109] Table 1 Calculation results of the soil on the outer side of the foundation pit

[0110]

[0111] Table 2 Calculation results of the soil on the inner side and the opposite side of the foundation pit

[0112]

[0113] Table 3 Calculation results of the soil on the inner side and the opposite side of the foundation pit

[0114]

[0115] Substitute the calculation results in the above table into the formula:

[0116]

[0117] For the convenience of comparison, check according to the specification formula, and the calculation model is as shown in Figure 5As shown in the figure, the calculation process table is as follows:

[0118] Table 4 Soil calculation results

[0119]

[0120] Substitute the calculation results in Table 4 into the formula:

[0121]

[0122] After calculation and comparison, when the foundation pit is an anchor-pulled or retaining deep and narrow foundation pit, the safety factor of the bottom heave resistance stability calculated by the improved formula is larger, and the required embedded length is more economical and reasonable.

[0123] In summary, the method for analyzing the bottom heave resistance stability applicable to narrow foundation pits in the present invention judges whether the current foundation pit is a narrow foundation pit; when the current foundation pit is a narrow foundation pit, based on the principle of the Swedish slice method, the soil body is divided into slices; the forces on the divided slices are analyzed to calculate the safety factor of the bottom heave resistance stability. Thus, over-deep embedding of the retaining structure can be avoided, and better social and economic benefits can be achieved.

[0124] At the same time, the embodiment of the present invention also provides a device for analyzing the bottom heave resistance stability applicable to narrow foundation pits, which includes a judgment module and a calculation module.

[0125] Among them, the judgment module is used to judge whether the current foundation pit is a narrow foundation pit; the calculation module is used to, when the current foundation pit is a narrow foundation pit, based on the principle of the Swedish slice method, divide the soil body into slices and analyze the forces on the divided slices to calculate the safety factor of the bottom heave resistance stability.

[0126] In some embodiments, the judgment module is configured to: draw an arc passing through the bottom of the retaining structure wall with the center of the lowest support point as the center of the circle, and when the radius of the arc is greater than the width of the foundation pit, it is determined as a narrow foundation pit.

[0127] In some embodiments, the calculation module is used to, when the current foundation pit is a narrow foundation pit, divide the soil body into slices based on the principle of the Swedish slice method, including:

[0128] Divide the soil outside the foundation pit into 9 slices with a width of 1 m;

[0129] Divide the soil inside the foundation pit into 6 slices with a width of 1 m;

[0130] Divide the soil on the opposite side of the foundation pit into 3 slices with a width of 1 m.

[0131] In some embodiments, the calculation module analyzes the forces on the divided slices and calculates the safety factor of the bottom heave resistance stability, including:

[0132] According to the formula:

[0133]

[0134] Calculate the safety factor of the bottom heave stability of the foundation pit ;

[0135] Wherein, is the safety factor of the bottom heave stability of the foundation pit;

[0136] is the self-weight of the i-th soil strip outside the foundation pit, calculated according to the natural unit weight;

[0137] is the self-weight of the j-th soil strip inside and on the opposite side of the foundation pit, calculated according to the natural unit weight;

[0138] is the width of the i-th soil strip outside the foundation pit;

[0139] is the width of the j-th soil strip inside and on the opposite side of the foundation pit;

[0140] is the length of the slip arc surface of the i-th soil strip outside the foundation pit;

[0141] is the length of the slip arc surface of the j-th soil strip inside and on the opposite side of the foundation pit;

[0142] is the angle between the normal line and the vertical line at the midpoint of the slip arc surface of the i-th soil strip outside the foundation pit;

[0143] is the angle between the normal line and the vertical line at the midpoint of the slip arc surface of the j-th soil strip inside and on the opposite side of the foundation pit;

[0144] is the internal friction angle of the soil at the slip arc surface of the i-th soil strip outside the foundation pit;

[0145] is the internal friction angle of the soil at the slip arc surface of the i-th soil strip inside and on the opposite side of the foundation pit;

[0146] is the cohesion of the soil at the slip arc surface of the i-th soil strip outside the foundation pit;

[0147] is the cohesion of the soil at the slip arc surface of the j-th soil strip inside and on the opposite side of the foundation pit;

[0148] is the ground surcharge borne by the i-th soil strip outside the foundation pit.

[0149] In summary, for the device for analyzing the anti-heave stability of the pit bottom applicable to narrow foundation pits in the present invention, it determines whether the current foundation pit is a narrow foundation pit through a judgment module; when the current foundation pit is a narrow foundation pit, based on the principle of the Swedish slice method, the soil body is divided into slices by a calculation module; and the forces on the divided slices are analyzed to calculate the safety factor of the anti-heave stability of the pit bottom. Thereby, over-deep embedment of the retaining structure can be avoided, and better social and economic benefits can be achieved.

[0150] The above is only the specific implementation manner of the embodiments of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the embodiments of the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for analyzing the anti - heave stability of the pit bottom applicable to narrow foundation pits, characterized in that, The method includes the following steps: Judge whether the current foundation pit is a narrow foundation pit; When the current foundation pit is a narrow foundation pit, divide the soil mass into slices based on the principle of the Swedish slice method; Conduct a force analysis on the divided slices and calculate the safety factor of the bottom heave stability of the foundation pit; The conducting a force analysis on the divided slices and calculating the safety factor of the bottom heave stability of the foundation pit includes: According to the formula: Calculate the safety factor of the anti-heave stability of the pit bottom ; In the formula, is the safety factor of the anti-heave stability at the bottom of the pit; It is the self-weight of the i-th soil strip outside the foundation pit, calculated according to the natural unit weight; It is the self-weight of the j-th soil strip on the inner side and the opposite side of the foundation pit, calculated according to the natural unit weight; is the width of the i-th soil strip outside the foundation pit; is the width of the j-th soil strip on the inner side and the opposite side of the foundation pit; is the sliding circular arc surface length of the i-th soil strip outside the foundation pit; is the length of the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit; is the included angle between the normal line and the vertical line at the midpoint of the sliding circular arc surface of the i-th soil strip outside the foundation pit; is the included angle between the normal line and the perpendicular line at the midpoint of the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit; is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip outside the foundation pit; is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip on the inner side and the opposite side of the foundation pit; is the cohesion of the soil at the sliding circular arc surface of the i-th soil strip outside the foundation pit; is the cohesion of the soil at the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit; It is the ground surcharge borne by the i-th soil strip outside the foundation pit.

2. The method for analyzing the anti-heave stability of the pit bottom applicable to a narrow foundation pit according to claim 1, characterized in that, The judging whether the current foundation pit is a narrow foundation pit includes: Taking the fulcrum of the lowest support as the center, draw an arc passing through the bottom of the retaining structure wall. When the radius of the arc is greater than the width of the foundation pit, it is determined as a narrow foundation pit.

3. The method for analyzing the anti-heave stability of the pit bottom applicable to a narrow foundation pit according to claim 1, wherein, The dividing the soil mass into slices based on the principle of the Swedish slice method when the current foundation pit is a narrow foundation pit includes: Divide the soil mass outside the foundation pit into 9 slices with a width of 1 m; Divide the soil mass inside the foundation pit into 6 slices with a width of 1 m; Divide the soil mass on the opposite side of the foundation pit into 3 slices with a width of 1 m.

4. A method for analyzing the anti-heave stability of the bottom of a narrow foundation pit according to claim 1, characterized in that: The depth of the foundation pit is 15 m and the width is 12 m.

5. The method for analyzing the anti - heave stability of the pit bottom applicable to narrow foundation pits according to claim 1, characterized in that: The soil unit weight is 19 kN / m 3 , the cohesion is 12 kPa, the internal friction angle is 18°, and the surcharge is 20 kPa.

6. An anti-heave stability analysis device for the bottom of a narrow foundation pit, characterized in that Includes: A judging module, which is used to judge whether the current foundation pit is a narrow foundation pit; A calculating module, which is used to divide the soil mass into slices based on the principle of the Swedish slice method when the current foundation pit is a narrow foundation pit, conduct a force analysis on the divided slices, and calculate the safety factor of the bottom heave stability of the foundation pit; The calculating module conducting a force analysis on the divided slices and calculating the safety factor of the bottom heave stability of the foundation pit includes: According to the formula: Calculate the safety factor of the anti-heave stability of the pit bottom ; In the formula, is the safety factor for the stability of the bottom heave resistance of the pit; It is the self-weight of the i-th soil strip outside the foundation pit, calculated according to the natural unit weight; It is the self-weight of the j-th soil strip on the inner side and the opposite side of the foundation pit, calculated according to the natural unit weight; is the width of the i-th soil strip outside the foundation pit; is the width of the j-th soil strip on the inner side and the opposite side of the foundation pit; is the length of the sliding circular arc surface of the i-th soil strip outside the foundation pit; is the length of the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit; is the included angle between the normal line and the vertical line at the midpoint of the sliding circular arc surface of the i-th soil strip outside the foundation pit; is the included angle between the normal line and the vertical line at the midpoint of the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit; is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip outside the foundation pit; is the internal friction angle of the soil at the sliding circular arc surface of the i-th soil strip on the inner side and the opposite side of the foundation pit; It is the cohesion of the soil at the sliding circular arc surface of the i-th soil strip outside the foundation pit; is the cohesion of the soil at the sliding circular arc surface of the j-th soil strip on the inner side and the opposite side of the foundation pit; It is the ground surcharge borne by the i-th soil strip outside the foundation pit.

7. The device for analyzing the anti-heave stability of the bottom of a narrow foundation pit according to claim 6, wherein, The judging module is configured to: take the fulcrum of the lowest support as the center, draw an arc passing through the bottom of the retaining structure wall. When the radius of the arc is greater than the width of the foundation pit, it is determined as a narrow foundation pit.

8. The device for analyzing the anti-heave stability of the pit bottom applicable to a narrow foundation pit according to claim 6, characterized in that, The calculating module is used to divide the soil mass into slices based on the principle of the Swedish slice method when the current foundation pit is a narrow foundation pit, including: Divide the soil mass outside the foundation pit into 9 slices with a width of 1 m; Divide the soil mass inside the foundation pit into 6 slices with a width of 1 m; Divide the soil mass on the opposite side of the foundation pit into 3 slices with a width of 1 m.

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