RU2018567C1 - Method for erection of foundation - Google Patents

Abstract

FIELD: construction. SUBSTANCE: method includes driving-in of hole by cylindrical tamper down to depth excluding ground emergence; tamping of rigid material into ground to form expanded foot and filling of hole with concrete. Expanded foot is arranged by successive forming of zones with help of driving-in of tamper of separate increasing in diameter as depth is increased. Diameter of zones and distances between their centers are determined by special relation. EFFECT: higher efficiency. 2 dwg

Description

 The invention relates to the construction, and in particular to methods of erecting foundations in punched wells.

 The purpose of the invention is to increase the bearing capacity of the foundation with a significant thickness of soft soils, simplifying manufacture and improving the reliability of the foundation.

, а уширенную пяту образуют путем последовательного формирования сверху вниз с последующей пробивкой трамбовкой отдельных увеличивающихся в диаметре по мере заглубления зон, при этом диаметр зон принимают равным
d_bri= d_c+2(h_ki-d)tgφ, а расстояния между центрами зон определяют по формуле
a_i,i+1=

, где N - статическое усилие, передаваемое на грунт в процессе трамбования, определяемое по формуле
N = Q+q +

, где Q - вес трамбовки;
q - вес первой зоны;
Н - высота сбрасывания трамбовки;
е - величина отказа трамбовки;
А_br - площадь поперечного сечения первой зоны;
r_br - радиус поперечного сечения первой зоны;

,

- соответственно удельный вес и удельное сцепление толщин грунта выше первой зоны, определенные как средневзвешенные значения нормативных величин;
N_j, N_q, N_c - безразмерные коэффициенты несущей способности, определяемые по таблице 7 СНиП 2.02.01-83 по средневзвешенному значению нормативных величин угла внутреннего трения

при угле наклона равнодействующей к вертикали δ =0,
d_c - диаметр скважины;
h_ki - глубина скважины от поверхности земли, соответствующая середине зоны;
d - глубина скважины, заполняемой бетоном, от поверхности земли до ее пересечения с первой зоной; φ - угол внутреннего трения грунта;
d_bri, d_bri+1 - диаметры соседних зон, определяемые по экспериментально-аналитической методике:
d_br= 2

, где V_br - насыпной объем втрамбованного в зону жесткого материала;
К_d - коэффициент уплотнения жесткого материала;
η - соотношение большой и малой полуосей зоны.The goal is achieved by the fact that in the known method of erecting a foundation, including punching a well with a cylindrical rammer, ramming hard material into the soil with the formation of an enlarged heel and filling the well with concrete, ramming the hard material begin at a depth determined by the formula
h _k1 =

and the broadened heel is formed by successive formation from top to bottom with subsequent punching by tamping of individual zones that increase in diameter as the depths deepen, while the diameter of the zones is taken equal
d _bri = d _c +2 (h _ki -d) tgφ, and the distances between the centers of the zones are determined by the formula
a _{i, i + 1} =

where N is the static force transmitted to the ground during tamping, determined by the formula
N = Q + q +

where Q is the weight of the tamper;
q is the weight of the first zone;
N - dumping height of the tamper;
e is the amount of failure of the tamper;
And _br is the cross-sectional area of the first zone;
r _br is the radius of the cross section of the first zone;

,

- respectively, the specific gravity and specific cohesion of the soil thicknesses above the first zone, defined as the weighted average values of standard values;
N _j , N _q , N _c - dimensionless load-bearing coefficients, determined according to table 7 of SNiP 2.02.01-83 by the weighted average value of standard values of the angle of internal friction

when the angle of inclination of the resultant to the vertical δ = 0,
d _c is the diameter of the well;
h _ki is the depth of the well from the surface of the earth, corresponding to the middle of the zone;
d is the depth of the well filled with concrete from the surface of the earth to its intersection with the first zone; φ is the angle of internal friction of the soil;
d _bri , d _{bri + 1} - the diameters of neighboring zones, determined by the experimental-analytical method:
d _br = 2

where V _br is the bulk volume of the hard material rammed into the zone;
To _d is the coefficient of compaction of a rigid material;
η is the ratio of the major and minor axis of the zone.

 In this case, the last zone is not punched with a tamper, and the well formed for its arrangement is filled with rigid material with its layer-by-layer compaction to the entire height of the broadened heel.

 In FIG. 1 shows the foundation, FIG. 2 is a diagram of the punching of a previously formed zone.

, где d_bri, d_bri+1 - диаметры соседних зон, определяемые по экспериментально-аналитической методике; φ - угол внутреннего трения грунта. В итоге уширенная пята фундамента имеет форму, близкую к круговому усеченному конусу с углом между наклонной образующей и вертикальной осью, близким к углу внутреннего трения грунта.The method of erecting the foundation includes punching the well 1 with a cylindrical rammer to a depth h _k1 , which excludes soil overburden, starting from which hard material can be rammed into the soil to form a widened heel, the formation of a system of successive zones 2 in the direction and in sequence from top to bottom by ramming hard material into the soil at the mark corresponding to the middle of each zone h _ki followed by punching by tamping of this zone to the mark corresponding to the middle of the next, deeper located zone h _{ki + 1} , fill hard material with its layer-by-layer compaction by tamping of the well formed during the construction of the last zone, which is punched by tamper, to the top of the first zone, filling the rest of the well with concrete 3 to a height of d. Moreover, the distance between the centers of neighboring zones is taken
a _{i, i + 1} =

where d _bri , d _{bri + 1} are the diameters of neighboring zones, determined by the experimental-analytical method; φ is the angle of internal friction of the soil. As a result, the broadened heel of the foundation has a shape close to a circular truncated cone with an angle between the inclined generatrix and the vertical axis close to the angle of internal friction of the soil.

 The use of the invention allows to significantly increase the depth and dimensions of the widened heel of the foundation and the compacted zone around it, which increases the bearing capacity of the foundation. The shape of the widened heel ensures the foundation works as a single rigid structure, increasing its reliability. The need to punch only one well and the use of no more than two materials for the construction of the foundation simplifies its manufacture.

To implement the method, cylindrical rammers with a mass of 2.5-5 tons and a diameter of 0.4-0.7 m, which are dumped from a height of 2-6 m, can be used. Crushed stone, concrete, blast furnace slag, glass breakage can be used et al. Depth h _k1 , starting from which hard material can be rammed into a well, is usually 4-15 m. The basic mechanism is the E-10011, E-652 excavators, the S-100, T-150 tractors, the KrAZ car and other

 The use of the invention allows to increase the bearing capacity of the foundation with a significant thickness of soft soils, to simplify the manufacture and increase the reliability of the foundation, to exclude soil outburst when building the foundation and to reduce the size of the foundation on the soil surface.

Claims (1)

METHOD FOR PRODUCING A FOUNDATION, including punching a well with a cylindrical rammer, ramming hard material into the soil with the formation of an enlarged heel and filling the well with concrete, characterized in that ramming the hard material begins at a depth determined by the formula
h _k1 =

,,
and the broadened heel is formed by successive formation from top to bottom, followed by punching by tamping of individual zones that increase in diameter as they deepen, while the diameter of the zones is taken equal
d _bri = d _c + 2 (h _ki -d) tgφ,
and the distance between the centers of the zones is determined by the formula
a _{i, i + 1} =

,
where N is the static force transmitted to the ground during tamping, determined by the formula
N = Q + q +

,
where Q is the weight of the tamper;
q is the weight of the first zone;
H is the dumping height of the tamper;
e is the amount of ramming failure;
A _br is the cross-sectional area of the first zone;
r _br is the radius of the cross section of the first zone;

,

- respectively, the specific gravity and specific adhesion of the soil thickness above the first zone, defined as the weighted average values of standard values;
N _j , N _q , H _with - dimensionless load-bearing coefficients, determined according to table 7 CH and P 2.02.01-83;
d _with - well diameter;
h _ri - well depth from the earth’s surface, corresponding to the middle of the zone;
d is the depth of the well filled with concrete, from the surface of the earth to its intersection with the first zone;
φ is the angle of internal friction of the soil;
d _bri , d _{bri + 1} - the diameters of neighboring zones, determined by the experimental-analytical method
d _br = 2

,
where V _br is the bulk volume rammed into the zone of rigid material;
K _d is the compaction coefficient of the rigid material;
η is the ratio of the major and minor axis of the zone.

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