def __init__(self, sp, pga=0.25, m_w=None, **kwargs):
self.sp = sp
assert isinstance(self.sp, sm.SoilProfile)
self.inc = 0.01
self.sp.gen_split(target=self.inc, props=['csr_n15'])
split_depths = np.cumsum(self.sp.split['thickness'])
self.depth = np.arange(0, sp.height + self.inc, self.inc)
self.npts = len(self.depth)
self.s_g = kwargs.get("s_g", 2.65)
self.s_g_water = kwargs.get("s_g_water", 1.0)
saturation = kwargs.get("saturation", None)
if m_w is None:
self.m_w = 7.5
else:
self.m_w = m_w
self.gwl = sp.gwl
self.pga = pga
if saturation is None:
self.saturation = np.where(self.depth < self.gwl, 0, 1)
else:
self.saturation = saturation
self.sigma_v = sp.get_v_total_stress_at_depth(self.depth) / 1e3
self.pore_pressure = sp.get_hydrostatic_pressure_at_depth(
self.depth) / 1e3
self.sigma_veff = self.sigma_v - self.pore_pressure
if self.sigma_veff[0] == 0.0:
self.sigma_veff[0] = 1.0e-10
self.rd = calc_rd(self.depth, self.m_w)
crr_unlimited = np.interp(self.depth, split_depths,
self.sp.split['csr_n15'])
self.crr_m7p5 = np.where(self.depth <= self.gwl, 4, crr_unlimited)
self.q_c1n_cs = calc_q_c1n_cs_from_crr_m7p5(self.crr_m7p5)
self.k_sigma = calc_k_sigma(self.sigma_veff, self.q_c1n_cs)
self.msf = calc_msf(self.m_w, self.q_c1n_cs)
self.crr = crr_m(self.k_sigma, self.msf,
self.crr_m7p5) # CRR at set magnitude
self.csr = calc_csr(self.sigma_veff, self.sigma_v, pga, self.rd,
self.gwl, self.depth)
fs_unlimited = self.crr / self.csr
self.factor_of_safety = np.where(fs_unlimited > 2, 2, fs_unlimited)
def compute_new_lsn_from_equivalent_profile(eq_profiler,
new_pga,
new_m_w,
n=3):
"""
Computes the Liquefaction severity number (LSN) for an equivalent soil profile
:param eq_profile: EquivalentSoilProfile object
:param new_pga: float, peak ground acceleration to consider LSN at
:param new_m_w: float, earthquake magnitude to consider LSN at
:return: float, LSN
"""
depth = eq_profiler.depth
gwl = eq_profiler.bi2014.gwl
if n == 3:
eq_qc1ncs = eq_profiler.e3_q_c1n_cs
crr_7p5 = eq_profiler.e3_crr_7p5
elif n == 5:
eq_qc1ncs = eq_profiler.e5_q_c1n_cs
crr_7p5 = eq_profiler.e5_crr_7p5
else:
raise ValueError
# compute msf
sigma_v = eq_profiler.bi2014.sigma_v
sigma_v_eff = eq_profiler.bi2014.sigma_veff
k_sigma = bi_functions.calc_k_sigma(sigma_v_eff, eq_qc1ncs)
msf = bi_functions.calc_msf(new_m_w, eq_qc1ncs)
rd = bi_functions.calc_rd(depth, new_m_w)
# compute CSR
csr = bi_functions.calc_csr(sigma_v_eff, sigma_v, new_pga, rd, gwl, depth)
# using the CRR and q_c1n_cs values compute the new FoS
eq_factor_of_safety = crr_7p5 / csr * k_sigma * msf
# using the new FoS and q_c1n_cs values compute the volumetric strain
eq_epsilon = lq.trigger.calculate_volumetric_strain(
eq_factor_of_safety, eq_qc1ncs)
lsn = lq.trigger.calculate_lsn(eq_epsilon, depth)
# using the volumetric strain and new FoS compute new lsn
return lsn
def test_calculate_msf():
magnitude = 7.5
q_c1ns = 84. * np.ones(1)
msf = bim14.calc_msf(magnitude, q_c1ns)
expected_msf = 1.
assert np.isclose(expected_msf, msf[0], rtol=0.001)
magnitude = 6.5
q_c1ns = 84. * np.ones(1)
msf = bim14.calc_msf(magnitude, q_c1ns)
expected_msf = 1.072
assert np.isclose(expected_msf, msf[0], rtol=0.001)
magnitude = 8.5
q_c1ns = 84. * np.ones(1)
msf = bim14.calc_msf(magnitude, q_c1ns)
expected_msf = 0.944
assert np.isclose(expected_msf, msf[0], rtol=0.001)
magnitude = 7.5
q_c1ns = 175. * np.ones(1)
msf = bim14.calc_msf(magnitude, q_c1ns)
expected_msf = 1.
assert np.isclose(expected_msf, msf[0])
magnitude = 6.2
q_c1ns = 175. * np.ones(1)
msf = bim14.calc_msf(magnitude, q_c1ns)
expected_msf = 1.514
assert np.isclose(expected_msf, msf[0], rtol=0.001)
magnitude = 5.1
q_c1ns = 175. * np.ones(1)
msf = bim14.calc_msf(magnitude, q_c1ns)
expected_msf = 2.1
assert np.isclose(expected_msf, msf[0], rtol=0.01)