KR101017567B1 - Design and construction method of Cast in place piles - Google Patents

Abstract

The present invention relates to a method for managing the design and construction of on-site placing piles using a computer, the location of the borehole and pile for inputting the location information of the borehole for the ground survey and the pile to be constructed into a computer that needs ground reinforcement And a borehole ground information input step of inputting ground information of the borehole into which the position is input to a computer; A borehole selection step of selecting a borehole into which the ground information to be used for analysis is input on a computer screen; Pile member force calculation step of calculating the member force of the pile by inputting the steel frame information to the computer; And by using all the information entered to examine the stability of each pile support and member forces pile stability review step to show on a computer screen; provides a design and construction management method of the site-placed piles.

Casting site, design program, construction program

Description

Design and construction method of Cast in place piles}

The present invention relates to a method for managing the design and construction of cast-in-place piles using a computer, and more particularly, to the design and construction management method of cast-in-place piles that are used as the foundation of high-rise structures at home and abroad will be.

As the weight of the upper structure increases, the use of cast-in-placement piles is increasing domestically and internationally.In the case of designing cast-in-place piles in Korea, designers often make calculations by manual labor. It takes a lot of design time and there is a problem that can not maintain a constant design quality because the standardized design method is not determined. In addition, the calculation of the ground constants used for the calculation of bearing capacity of cast-in-placement piles depends on the designer's supervision, so the design was not reasonable. At present, the design and construction management are separated so that the quality management of the pile cannot be rationalized. there was. Therefore, there was a need for an optimized design method that can apply ground constants reasonably, perform individual pile design simultaneously, and be convenient for users.

The purpose of the present invention is to enable the rapid and accurate design management of cast-in-place piles, to realize the optimized design by obtaining the rational design ground constant, and to automatically calculate the designed construction quantity. It also aims to make active use in turnkey design and design changes.

The present invention relates to a method for managing the design and construction of on-site placing piles using a computer, the location of the borehole and pile for inputting the location information of the borehole for the ground survey and the pile to be constructed into a computer that needs ground reinforcement And a borehole ground information input step of inputting ground information of the borehole into which the position is input to a computer; A borehole selection step of selecting a borehole into which the ground information to be used for analysis is input on a computer screen; Pile member force calculation step of calculating the member force of the pile by inputting the steel frame information to the computer; And by using all the information entered to examine the stability of each pile support and member forces pile stability review step to show on a computer screen; provides a design and construction management method of the site-placed piles.

The present invention supplements the point that the existing design method of the pile using a computer can be calculated only for one pile to enable a review of the entire cast-in-place pile to be constructed in the field, the ground survey position information of the cast-in-place pile By directly importing the CAD file containing the data, the computer recognizes the exact location of the design object and applies it to the design. In addition, it included a function to design by directly displaying the location of the site cast pile and the ground survey location, it was configured by inputting using absolute coordinates / relative coordinates for the convenience of the designer. Finally, the present invention is conveniently configured to obtain the results of the pile load test under ground conditions other than the general design method.

The present invention relates to a method for managing the design and construction of a cast-in-place pile using a computer,

Input location information of the borehole and pile to input the location information of the borehole and the pile to be constructed to the site for the site reinforcement; and the ground information of the borehole inputted into the computer An input step; and a pile specification input step of inputting a specification of the pile into which the position is input; Selecting a bearing capacity calculation method for selecting a bearing capacity of the pile to be a computer screen; And a pile member force calculation step of calculating the member force of the pile by inputting the reinforcing steel or steel frame information used in the pile to the computer; And by using all the information entered to examine the stability of each pile support and member forces pile stability review step to show on a computer screen; provides a design and construction management method of the site-placed piles.

In another aspect, the present invention, the information input in the position information input step of the borehole and the pile is characterized in that by the method of importing the CAD file or directly input to the computer.

In addition, the present invention, the method of selecting the borehole in the borehole selection step is to select the borehole closest to the pile to be constructed, to use the average value by selecting two boreholes closest to the pile to be constructed or in the field It is characterized by the method of any one of selecting the one with the weakest physical properties of the borehole drilled.

In addition, the present invention, the bearing capacity calculation method selected in the bearing capacity calculation method selection step is characterized in that any one or more of the basic structure design standards, road bridge design standards, railway design standards, FHWA, AASHTO, Canadian Foundation Engineering or Samsung Yonsei standards .

In addition, the present invention, in the support capacity calculation method selection step, the selected bearing capacity calculation method is based on the Samsung Yonsei University, characterized in that it further comprises an additional property value input step for inputting additional property values to the computer to apply the Samsung Yonsei standard. It is done.

In addition, the present invention, when the stability stability of the pile used in the pile stability review step is calculated by calculating the tip bearing force and peripheral friction of each pile with the input information is greater than the vertical force acting on each pile It is characterized by judging by stability.

In another aspect, the present invention, the method for examining the stability of the pile used when the sub-friction force acts in the pile stability review step is calculated by calculating the tip bearing capacity and peripheral friction of each pile with the input information acting on each pile If it is greater than the sum of the vertical force and the sub-frictional force is characterized by judging as stable.

In addition, the present invention, after the pile stability review step, complete the construction of the cast-in-place pile and input the construction pile and construction layer information to the computer to compare with the pile and stratum information input before the construction to show on the computer screen Characterized in that it further comprises a construction comparison step.

In addition, the present invention, the actual construction comparison step,

A pile and stratum information comparison report for before and after construction is generated and includes a display on a computer screen.

In another aspect, the present invention is characterized in that it further comprises an experimental result showing the step of drawing a graph showing the head sedimentation amount or the distribution during celebration after the pile stability review step.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Figure 1 shows a flow chart showing the order in which the present invention is implemented. As shown in FIG. 1, the present invention comprises a borehole and pile location information input step, borehole ground information input step, pile specification input step, borehole selection step, bearing force calculation method selection step, pile member force calculation step and pile stability review step. In addition, an actual construction comparison step may be provided. In addition, the actual construction comparison step may include generating a comparison report by comparing before and after construction. In addition, a test result may be provided.

Hereinafter, each step will be described in detail with reference to the accompanying drawings.

2 shows an initial screen of the present invention executed on a computer.

In the step of inputting the borehole and piles, the position of the borehole to find the ground information at the designated site is placed on the computer, and the placement positions of the piles are selected and input on the computer screen. 3 is a screen for selecting a method of inputting the location information of the borehole and the pile, the CAD file may be loaded or directly input. Figure 4 (a) shows the appearance of loading the CAD file on the screen, when loading the CAD file, the position of the pile, the ground survey location, the site outline, etc. that are necessary for the design is automatically read. Several elements imported from the CAD file are automatically created for use in the design. Figure 4 (b) is a form of directly inputting the site outline, the location of the borehole, the position of the pile and the like directly on the computer while looking at the computer screen. The direct input method can be selected from the absolute coordinate method that inputs the position based on the absolute reference and the relative coordinate method that inputs the position relative to the first point or the previous point. One or more boreholes may be input according to the user's selection, and one or more piles may be input according to the selection.

The borehole ground information input step is a step of inputting the ground information of the borehole into which the position is input to the computer. The borehole is to calculate the stability of the pile by providing the ground information, and the ground information is extracted from the borehole drilled by the ground boring at the actual site, and the ground information is input to the computer for each borehole to calculate the stability of the pile. It is. The ground information to be input is the depth information according to the depth of the ground, the type of strata, the thickness of each strata, the internal friction angle, the uniaxial compressive strength, the elastic modulus, the RQD, etc. for each strata type (see FIG. 5). Each borehole is given a number to conveniently enter the ground information for each borehole. In addition, the borehole for inputting the ground information is displayed in color on the drawing to facilitate the inputter. This ground information will be used in the case of calculating the tip bearing capacity, peripheral friction force, etc. in the process of examining the stability of the pile below.

The pile specification input step is a step of inputting the specifications of each pile input the position into the computer. This is the step of entering the information of each pile to be entered underground. Numbers are assigned to each pile for the convenience of the inputter, and the input information includes pile diameter, pile effective diameter, pile length, vertical force acting on the pile, casing length, excavation depth, embedding depth, concrete pouring amount (Con ' c), the coefficient applied to the amount of concrete pouring is input. As a result, the applied concrete (applied Con'c) calculated by multiplying the concrete pouring amount and the application coefficient is automatically calculated, and the inputted information is recognized by the computer (see FIG. 6).

The borehole selection step is to select the borehole to use the ground information to be applied to the stability evaluation of each pile. Since many boreholes are usually drilled to extract ground information from the site, it is necessary to select which borehole to apply to each pile. One is to select the borehole closest to each pile, and the other is to select the two boreholes closest to each other and use the average value of each ground information, and three to select the one with the weakest physical properties among the boreholes. It is the method of making it maximum (refer FIG. 7). If you select the borehole closest to each pile, it is difficult to cope with the sudden change of the ground, and the disadvantage of this is to use the average value by selecting two boreholes close to the pile. If the stability is to be maximized, the one with the weakest physical property among the boreholes may be selected.

The supporting force calculation method selection step is a step of selecting one or more according to a user's selection from among known bearing capacity calculation methods (see FIG. 8). The bearing capacity calculation method is well known, and there are structural basic design standards, road bridge design standards, and railway design standards as domestic design standards, and FHWA, AASHTO, and Canadian Foundation Engineering methods as foreign design standards. There is one Samsung Yonsei standard. The above standards are stored in a database in advance in a computer. To Figure 4. In addition, Samsung Yonsei standards are described separately.

Figure 1. Structural Design Standard and Road Bridge Design Standard

Figure 2. Railway design criteria

Figure 3. FHWA and AASHTO

Figure 4. Canadian Foundation Engineering

Samsung Yonsei's standard is not a well-known method of calculating bearing capacity, and it corresponds to a new formula developed by Samsung Yonsei University. As a result of analysis of previous studies and results of this study, the influence factors of sage cast pile q _max can be summarized as the strength of the cancer, the distance between the discontinuities, the slope of the discontinuities, the constraint stress, and the type of cancer. In consideration of the ground survey results and practical applicability, the strength and discontinuity spacing of the cancer are selected as the main influence factors, and the q _max equation is proposed as follows.

q _max = k (q _u / P _a ) ^λ (S _j / D) ^μP _a

(q _u : uniaxial compressive strength of tip arm, S _j : discontinuous surface spacing, D: pile diameter, P _a : atmospheric pressure, k: 12.5, λ: 0.8, μ: 0.5)

k, λ, μ are the strength constants and are suggested as the optimum values described above based on domestic loading test data, and the discontinuity spacing (S _j ) can be assumed to be the inverse of the frequency of the inferior flux (= 1 / λ _j ). And Hudson (1976) suggest the relationship between the RQD and the discontinuity frequency (λ _j ). Priest and Hudson (1976) proposed the following equations based on field data measured in Lower Chalk and Chinor, UK as shown in Figure 5.

Figure 5. Relationship between RQD and mean frequency of discontinuities (after Priest and Hudson, 1976)

The pile member force calculation step is a step of calculating the member force of the pile in consideration of the reinforcing steel or steel frame used in the cast-in-place pile (see (a), (b) of Figure 9). It is common to cast concrete in the cast-in-place pile, and reinforcement or steel frame is inserted into the concrete to compensate for the disadvantage of concrete. In view of this, the present invention is classified into two options.

First, when the reinforcing bar is inserted, the type, number, and yield strength of the vertical reinforcing bar are input, and the type, interval, and coefficient of the band reinforcing bar are input. By using this, the member force (P _n ) is calculated and compared with the vertical force (= axial load, P) input in the pile specification input stage, and the stability of the vertical load is examined, and the required reinforcing cross section area and the applied reinforcing cross section area are compared. Examine the stability of the band reinforcing bars.

-Review the vertical load of the rebar P _n  > P OK )

σ _{ck '} = reduction factor × σ _ck (design reference strength of underwater concrete)

σ _ca = 0.40 × σ _{ck '}

σ _sa = 0.5 × σ _y ≤ 1,600 kg / cm ² (members installed below water level and below ground level)

(σ _{ck '} : concrete strength in water (kg / cm ² ), σ _ck : used concrete strength (kg / cm ² ), σ _ca : permissible compressive stress (kg / cm ² ), σ _sa : permissible stress in rebar (kg / cm ² ), σ _y : yield strength of rebar)

P _n (Absence) = 0.85 [σ _ca × (A _g -A _st ) + σ _sa × A _st ]

(A _g : Total cross section of the pile (cm ² ), A _st : Total cross section of rebar (cm ² ), σ _ca : Permissible compressive stress (kg / cm ² ), σ _sa : Permissible stress of rebar (kg / cm ² ))

- Steel bars  Review( A _s   > A _s'  If, OK )

A _S '= 0.001 × D × a

(A _s' : required rebar cross-sectional area (cm2) of strip reinforcing bars, D: diameter of pile (cm), a: spacing of strip reinforcing bars (cm))

As: The cross-sectional area of the reinforcing steel bar (cm2). When the reinforcing bar data is input, it is automatically calculated by the formula for rebar diameter and circle area. [Pressing []] of the type of rebar shown on the screen shows the cross section of the desired rebar.]

Next, when steel is inserted, the vertical steel, root depth, steel length, yield strength, and the like, by calculating the absent force (P _n ) of the calculated steel composite portion by the vertical force input in the pile specification input step Examine whether or not the vertical load is stable compared to (= axial load, P), calculate the absent force (P _n ) of the root part, and compare it with the vertical force (= axial load, P) input in the pile specification input step. Further check the stability of the load.

-iron frame Synthesis section  At review ( P _n  > P OK )

P _n (Absence) = 0.4 × 0.85 [σ _ca × (A _g -A _st ) + σ _sa × A _st ]

(A _g : Total cross section of the pile (cm ² ), A _st : Total cross section of steel (cm ² ), σ _ca : Permissible compressive stress of concrete (kg / cm ² ), σ _sa : Permissible stress of steel (kg / cm ² ))

-In case of root inspection (if P _n > P, OK )

P _n (Absence) = 0.4 × 0.85 [σ _ca × A _g ]

(A _g : Total cross section of pile (cm ² ), σ _ca : Permissible compressive stress of concrete (kg / cm ² ))

The pile stability review step is the step of calculating the tip bearing capacity, peripheral friction force, and sub-friction force of the pile according to the calculation method selected in the selection method of the bearing capacity calculation step, and comparing it with the allowable bearing force to determine the stability of the pile and showing it on the computer screen. See FIG. 10).

Judgment method, if there is no sub-frictional force, the stability review method of each pile is the inputted information, and the value calculated by calculating the tip bearing capacity and the peripheral frictional force of each pile is judged to be stable if it is larger than the vertical force acting on each pile. For example, if there is negative frictional force, the value obtained by calculating the tip bearing capacity and the peripheral frictional force of each pile is greater than the sum of the vertical force and the negative frictional force acting on each pile.

In addition, in this step, the results of the stability review of the pile can be displayed on the computer screen in the form of a report, thereby saving the effort of preparing a separate report. When a plurality of bearing capacity calculation methods are selected, it is possible to display on the report that the plurality of bearing forces is calculated according to the plurality of bearing capacity calculation methods.

The actual construction comparison step is a step of showing on the computer screen compared with the pile and the ground information input before the construction when the construction floor information after the construction of the pile into the computer (see Figure 12). This step shows that the present invention enables construction management as well as the design of the cast-in-place pile, allowing comparison with the designed pile after construction is completed. In addition, this step may include generating a pile and stratum information comparison report on the computer screen before and after construction (see FIG. 13). This is to finish the construction and compare the pile and ground information entered before the construction and the pile and ground information entered and completed the construction to complete the report to show on the computer screen.

Experimental results shown in the step is a special function that only the present invention is a step to obtain the effect of the experiment in the actual field. In other words, in order to experiment in actual field, it is difficult because not only various equipment and manpower are mobilized but also time consuming. In order to solve this problem, the present invention can show the same result as the experiment by inputting the physical property values of the ground and the pile by adding the experimental result city step. However, this step can be used only when the Samsung Yonsei Standard is used as a support calculation standard. In order to utilize this step, the wet unit weight (γ _t ), the saturation unit weight (γ _sat ), the elastic modulus of rock (E _mass , or E), and the elastic modulus of rock are shown on the screen shown in FIG. E _intact ), uniaxial compressive strength of the rock (q _u ), Poisson's ratio (v), roughness element height (Seg.Height), roughness element length (Seg.length), GSI, material constant of solid rock (m _i ) and You must enter an RQD. By input of these elements, a graph showing the head loading amount or the distribution during the celebration is drawn by the equation described below (see FIGS. 15A and 15B). The formula is explained below.

- Friction Transition function

Figure 6 below is a graph showing the principal load transfer characteristics of the cast-in-placement piles in the rock, and the following equation is expressed by the formula.

Where σ _ci = uniaxial compressive strength of rock, σ _normal = vertical stress at pile-rock interface, σ _tm = tensile strength of rock = -sσ _ci / m _b , σ _ini = initial vertical stress, B = GSI Strength constant, i = surface roughness angle, s, m _b = Hoek-Brown material constant of rock, w = displacement at pile-rock interface, w _st = maximum displacement of elastic behavior, w _max = maximum peripheral surface Displacement amount of frictional force, K _N = vertical rigidity of rock. In the present invention, each variable of the RG model is determined by the inputted physical property value, the Geological Strength Index (GSI), the material constant (m _i ) of the solid rock, the segment length and the segment height. GSI is a qualitative value representing the decrease in the strength of the ground as rock joints and weathering develop, and are shown in Figure 7 and correlated with the rock mass rating RMR ₈₉ (rock mass rating; Bieniawski, 1989) or Q-value as shown below. It can also be obtained from an equation. However, when the RMR ₈₉ value is applied, the groundwater estimate and the joint direction estimate are assumed to be 15 and 0, respectively.

_{GSI = RMR 89 - 5 (RMR} 89> 23)

GSI = 9 log _e Q + 44 (RMR ₈₉ <23)

The material constant (m _b ) of the rock is determined from the material constant (m _i ) of the rock and the GSI. Where m _i can be estimated from rock triaxial compression tests, or the results of existing studies can be used as shown in Table 1. Segment length (Segment length, ≒ 2l _a ) and Segment height (Δr) can be quantified using Monash method (Seidel and Harberfield, 1995) based on the excavation surface roughness measurement results.

However, if it is difficult to measure the roughness of the excavated surface, it is recommended that the element length is 50mm (l _a ≒ 25mm) regardless of the type of cancer, and that the element height is 4mm and 2mm, respectively, according to the RCD excavation method and all casing excavation method.

Figure 6. Principal Load Transfer Characteristics of Cast-In Place Pile in Rock Formation

Figure 7. Geological Strength Index (GSI)

Table 1. M _{i of} rocks according to the type of cancer (Marinos and Hoek, 2001)

Although the present invention has been described with reference to the accompanying drawings as mentioned above, various modifications and variations are possible without departing from the spirit of the present invention, and may be used in various fields. Therefore, the claims of the present invention include modifications and variations that fall within the true scope of the invention.

1 is a flow chart showing the order in which the present invention is implemented.

2 is an initial screen of the present invention executed on a computer.

3 is a position information input method selection screen of the borehole and the pile.

4 is a position information input method of the borehole and the pile (a) is a method of directly importing a CAD file, (b) is a method of directly inputting on a computer screen.

5 is a screen for inputting the ground information of the borehole.

6 is a screen for inputting the specifications of the pile.

7 is a screen for selecting a borehole to be used for stability review of the pile.

8 is a screen for selecting a bearing capacity calculation method.

9 is a screen for calculating the member force of the pile, (a) is a screen for selecting the steel bar as the type of the member, (b) a steel frame as the type of the member.

10 is a screen showing the results of examining the stability of the pile.

11 is a screen showing a state of reviewing the stability of each of the bearing capacity calculation method used to examine the stability of the pile.

12 is a screen showing comparing the pile and ground information input before and after the actual construction.

13 is a screen showing a comparison report generated with respect to the pile and ground information input before and after the actual construction.

14 is a screen for inputting additional physical properties by selecting the Samsung Yonsei criteria as a bearing capacity calculation method.

15 is a screen showing the results obtained by experiments in the actual field by selecting the Samsung Yonsei standard, (a) the head settlement settlement of the pile, (b) the screen showing the results of the distribution test of the pile.

Claims (13)

To manage the design and construction of a cast-in-place pile using a computer, Inputting the location information of the borehole and the pile into the computer to input the location information of the borehole and the pile to be constructed for the ground survey on the site requiring the ground reinforcement; Borehole ground information input step of inputting the ground information of the borehole with the position input to the computer; A pile specification input step of inputting a specification of the pile into which the position is input; A borehole selection step of selecting a borehole into which ground information to be used for analysis of the pile to be constructed is input on a computer screen; Selecting a bearing capacity calculation method for selecting a bearing capacity of the pile to be constructed on a computer screen; A pile member force calculation step of calculating a member force of the pile by inputting reinforcing bars or steel frame information used for the pile to be constructed into a computer; And The design and construction management method for the site-casting pile, characterized in that consisting of; the pile stability review step of showing on the computer screen by examining the stability of the support and member forces of each pile by using all the information entered. In claim 1, The information input at the position information input step of the borehole and the pile is the design and construction management method of the site-pouring pile, characterized in that by the method of loading the CAD file. In claim 1, Borehole and pile information input in the position information input step of the borehole and the pile is a design and construction management method of the site-pouring pile, characterized in that the direct input to the computer. In claim 1, The method of selecting a borehole in the borehole selection step includes designing and constructing a construction management method of a site-pouring pile, characterized in that by selecting a borehole closest to a pile to be constructed. In claim 1, The method of selecting a borehole in the borehole selection step includes designing and constructing a method for constructing a site-pouring pile, wherein the average value is selected by selecting two boreholes closest to the pile to be constructed. In claim 1, The method of selecting the borehole in the borehole selection step is the design and construction management method of the site-pouring pile, characterized in that for selecting the one with the weakest physical properties of the borehole drilling in the field. In claim 1, The bearing capacity calculation method selected at the step of selecting the bearing capacity calculation method may be any one or more of the following: basic design criteria, road bridge design criteria, railway design criteria, FHWA, AASHTO, Canadian Foundation Engineering, or Samsung Yonsei University. And construction management methods. According to claim 1, In the step of selecting the bearing capacity calculation method, The calculation method of bearing capacity is based on Samsung Yonsei University. Design and construction management method of the cast-in-place pile, characterized in that it further comprises an additional input step of inputting the physical properties to the computer to apply the Samsung Yonsei standard. In claim 1, The stability review method of the pile used in the pile stability review step is to determine the stability if the value added by calculating the tip bearing and peripheral friction of each pile with the input information is greater than the vertical force acting on each pile Design and construction management method of the cast-in-place pile. In claim 1, In the pile stability reviewing step, the method of examining stability of the pile used when the sub frictional force acts is calculated by calculating the tip support force and the peripheral friction force of each pile with the inputted information. The method of design and construction management of the cast-in-place pile, characterized in that it is judged to be stable if it is larger than the summed value. The method according to any one of claims 1 to 10, After the pile stability review step, finish the construction of the cast-in-place pile and input the constructed pile and construction ground information into the computer and add the actual construction comparison step to show on the computer screen by comparing the pile and ground information input before the construction. Design and construction management method of on-site pour pile, characterized in that provided with. The method of claim 11, wherein the actual construction comparison step, Design and construction management method of the cast-in-place pile, characterized in that the generation report before and after the pile and stratum information comparison report is generated and displayed on the computer screen. In claim 8, Design and construction management method of the cast-in-place pile, characterized in that it further comprises an urban step of the experimental result to draw a graph showing the head sedimentation amount or the distribution during celebration after the pile stability review step.

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